CLINICAL STUDIES ON THE DIAGNOSIS AND SURGICAL MANAGEMENT OF CORNEAL ULCERATION AND

CATARACT IN DOGS

Dissertation

Submitted to the Guru Angad Dev Veterinary and Animal Sciences University

in partial fulfillment of the requirements for the degree of

DOCTOR OF PHILOSOPHY in

VETERINARY SURGERY AND RADIOLOGY (Minor Subject: Veterinary Anatomy)

By

Rayees Ahmad Rather (L-2012-V-28-D)

Department of Veterinary Surgery and Radiology College of Veterinary Science

©GURU ANGAD DEV VETERINARY AND ANIMAL SCIENCES UNIVERSITY LUDHIANA - 141004

2016

CERTIFICATE I

This is to certify that the dissertation entitled, “Clinical studies on the

diagnosis and surgical management of corneal ulceration and cataract in dogs”

submitted for the degree of Ph.D., in the subject of Veterinary Surgery and

Radiology (Minor subject: Veterinary Anatomy) of the Guru Angad Dev Veterinary

and Animal Sciences University, Ludhiana, is a bonafide research work carried out by

Dr. Rayees Ahmad Rather (L-2012-V-28-D) under my supervision and that no part

of this thesis/ dissertation has been submitted for any other degree.

The assistance and help received during the course of investigation have been

fully acknowledged.

_______________________________________

(Dr. N. S. Saini)

Major advisor

Professor,

Dept. of Veterinary Surgery and Radiology

Guru Angad Dev Veterinary and Animal Sciences

University, Ludhiana-141004, Punjab (India)

CERTIFICATE II

This is to certify that the dissertation entitled, “Clinical studies on the

diagnosis and surgical management of corneal ulceration and cataract in dogs”

submitted by Dr. Rayees Ahmad Rather (L-2012-V-28-D) to the Guru Angad Dev

Veterinary and Animal Sciences University, Ludhiana, in partial fulfillment of the

requirements for the degree of Ph.D., in the subject of Veterinary Surgery and

Radiology (Minor subject: Veterinary Anatomy) has been approved by the

Student‟s Advisory Committee after an oral examination on the same, in collaboration

with an external examiner.

____________________ ___________________________

(Dr. N. S. Saini) (Dr. Adarsh Kumar)

Major advisor External Examiner

Professor

Dept. of Surgery & Radiology

CSK HP Krishi Vishawvidyalya

Palampur – 176062 (HP)

_____________________

(Dr. J. Mohindroo)

Head of the Department

_______________________

(Dr. S. S. Singh)

Dean, Postgraduate Studies

ACKNOWLEDGEMENTS

Today culminating this arduous task of Doctor of Philosophy, I am reminder of many events, many words and many hands that helped me learn, enlighten my thoughts and made me move forwards in life. It is hard to acknowledge sincere help with mere words. Still I must try.

Try to pen down my feelings, the very deep sense of gratitude and indebtness shapes down towards my eminent guide Dr. Narinder Singh Saini Professor Department of Veterinary Surgery and Radiology, for his constant untiring encouragement, moral support, constructive criticism, timely suggestions and vigilant supervision that led to successful completion of the present investigation

The words fall short to express my whole hearted sense of gratitude and indebtedness towards kind hearted respected teachers Dr. Simrat Sagar Singh, Dean Post Graduate studies COVS, GADVASU and Dr. Shashikanth Mahajan Professor and Dean PG”s Nominee, Department of Veterinary Surgery and Radiology for their meticulous guidance and consistent support.

I render my sincere thanks to the members of advisory committee: Dr.Jitender Mohindroo Professor cum Head, Department of Veterinary Surgery and Radiology, Dr.C.S.Randhawa, Professor, Department of Veterinary Medicine and Dr.Neelam Bansal, Professor Department of Veterinary Anatomy for their kind cooperation and suggestions during the course study.

I express my sincere and subterranean sense of gratitude to Dr.Vandana Sangwan for her constant supervision and constructive criticism which was the best kind of encouragement. I am sincerely thankful to faculty members of department Dr.Navdeep Singh, Dr.Arun Anand, Dr.Ahwani Kumar, Dr.Pallavi Verma ,Dr. Tarunbir Singh and Dr.Rahul Udheiya for all the knowledge they have imparted and all the help they have rendered during the research work.

Words would not suffice to express my deepest sense of gratitude to my senior Dr. Prachi E. Taksande for lending her helping hand when I really needed.

Friendship is forever and is quite true about Mudasir, Rameez, Najeeb, Umar, Maneesh, Sumit,Aabid, Suhail, Aashiq, Feroze, Abishiekh, Riyaz ,Qayoom, Umeshwori Devi, Aarif and Aijaz. I thanks to them for their precious friendship, backstairs influence, everlasting contribution, moral support and help for successful completion of my research work.

I would like to thank Dr. yaseen, Jasmeet, Himangshu, Deepesh, Anubhav, Chandan, and all the juniors Jasleen,Khalid, Anil, Satinderpal, Manpreet, Shriraam, Taran, Salisha, Hunny, Gurwinder, Ritu, Anupreet, Arshdeep,Rozzel, Gurnoor, Ankit, Krystle, Balaji, Navjot, Shameena, Shanib, Surbi, Ramneet, Kiran, Aman and Balpreet for all the good memories. I would like to acknowledge all the non-teaching staff of the department and clinics for their cooperation and help.

I am grateful to Department of Science and Technology New Delhi for providing necessary funds which helped me to complete this venture successfully.

Indeed the words at my command are inadequate either in the form of spirit to convey the depth of my feeling of gratitude and expressing my salutes to my loving father Haji Mohmad Ahsan Rather, my mother Mrs. Raja Banoo,uncle Haji Abdul Raheem Rather and my aunty Taja Banoo for their sacrifice, inspiration, affection, encouragement, moral support to take up the challenge and achieve the mile stone I could never have reached to. My showers of love and blessings to my brothers Mr. Shabir Ahmad, Abdul Rashid, Nazir Ahmad, Mohd Saleem, Muzamil, Mohsin, Ehsaan sisters Miss Raziya Gowher, Shakeela Raheem and Nighat Jan and little kids Saniya, Rehnuma, Muntaha, Rutba and Hinan.

Above all I thank almighty Allah for giving me patience and strength to overcome the difficulties, which came across in my way in accomplishment of this endeavor.

Place: Ludhiana Date: Dr. Rayees Ahmad Rather

Title of the Dissertation : “Clinical studies on the diagnosis and surgical

management of corneal ulceration and cataract in dogs”

Name of the student and

Admission No.

Rayees Ahmad Rather

L-2012-V-28-D

Major Subject : Veterinary Surgery and Radiology

Minor Subject : Veterinary Anatomy

Name and Designation : Dr Narinder Singh Saini

Professor

Degree to be Awarded Doctor of Philosophy

Year of Award of Degree : 2016

Total pages in Dissertation : 83 + VITA

Name of the University : Guru Angad Dev Veterinary and Animal Sciences

University, Ludhiana-141004, Punjab (India)

ABSTRACT

Study was conducted on 48 clinical cases of dogs suffering from cataract (n=27) and corneal

ulceration (n=21). All the animals were divided in two groups i.e group I (n=27) comprised of

cataract and group II (n=21) consisted of corneal ulcer affected cases. After phacoemulsification in

group IA (n=5) rigid Polymethylmethacrylate (PMMA) lens and in group IB (n=22) foldable square

edge acrylic lens were implanted. Group II was also sub divided in to group IIA (n=8) in which

corneal scarification was done by grid (n=4) and multiple punctate (n=4) keratotomy, group IIB

(n=5) in which both corneal scarification and conjunctival grafting was used and group IIC (n=8) in

which only conjunctival grafting was done. Results of group I, showed that cataract was common in

middle aged male dogs. High incidence was seen in German Shepherd followed by Labrador. Study

indicated senility and diabetes as the causative factor for the development of bilateral mature

cataract. Menace, pupillary light reflex, obstacle course test, tonometry, ophthalmoscopy and ocular

biometric analysis including A-mode ultrasonography and Pachymetry were effective for evaluating

the different segments of eye and to check the possibility of retinal disease and optic nerve

pathology. Tropicamide, atropine eye drops and intracameral adrenaline achieved satisfactory

pupillary dilatation and facilitated lens manipulation during surgery. One handed

phacoemulsification technique was successfully performed through a 2.8 mm clear corneal incision.

Group IB (foldable acrylic lens) animals showed quick corneal healing, fewer complications, more

rapid visual recovery and significantly higher success rate than group IA (rigid

polymethylmethacrylate). Success rate in group IA and group IB was 20% and 68% respectively.

However, intraoperative complications observed were, hyphema and pupillary constriction where as

post-operative complications were corneal opacity and uveitis. Dogs in group II, suffering from

corneal ulceration showed high incidence in young male Pug dogs. Study showed that

lagophthalmos followed by trauma were the most common cause with symptoms like conjuctival

hyperaemia and corneal opacity. Fluorescein dye test helped in proper diagnosis of ulcer in dogs.

Gentamicin and Carboxy methyl cellulose sodium drops helped in minimizing post operative

bacterial infection. Complete healing of corneal ulcers was achieved on 7th post operative day in all

animals of group IIA that had undergone grid keratotomy while half of the animals showed

complete healing where multiple punctate keratotomy was used. In group II B, overall 80% in group

II C, 87.5% success rate were achieved by 15th

postoperative day. Common post operative

complications in group II B and II C were breakage of graft, scar formation and corneal opacity.

Keywords: Canine, Cataract, Corneal ulcer, Phacoemulsification, Polymethylmethacrylate and

Acrylic lens, Corneal opacity, Keratotomy, Conjuctival grafting

________________________ ____________________

Signature of Major Advisor Signature of the Student

CONTENTS

CHAPTER TOPIC PAGE NO.

I INTRODUCTION

1 – 4

II REVIEW OF LITERATURE

5 – 27

III MATERIALS AND METHODS

28 – 40

IV RESULTS AND DISCUSSION

41 – 64

V SUMMARY

65 – 68

REFERENCES

69 - 83

VITA

LIST OF TABLES

Table no. Title Page no.

1 Brief outline of the study conducted on cataract and corneal ulceration

cases in dogs.

28

2 Age wise distribution of canine cataract cases (Group I) 41

3 Sex wise distribution of canine cataract cases (Group I) 42

4 Breed wise distribution of canine cataract cases (Group I) 42

5 Classification of canine cataract cases (Group I) 43

6 Stage of canine cataract cases (Group I) 43

7 Occurrence of canine cataract cases (Group I) 44

8 Haematobiochemical (Mean±SE) parameters of canine cataract cases

(Group I)

44

9 Preoperative calculation of different ocular biometric parameters in

Canine cataract cases (Group I)

45

10 Age wise distribution of corneal ulceration cases (Group II) 56

11 Breed wise wise distribution of corneal ulceration cases (Group II) 57

12 Sex wise distribution of corneal ulceration cases (Group II) 57

13 Causative factor of corneal ulceration cases of (Group II) 58

14 Location of corneal ulceration cases (Group II) 59

LIST OF FIGURES

Fig no. Title

1 Panoptic Direct Ophthalmoscope

2 Indirect ophthalmoscope with 20 D lens

3 Fluorescein dye strips and Schirmer‟s tear test strips

4 Photograph showing Schirmer's Tear Test in a dog

5 Photograph showing measurement of IOP using Tonopen in a dog

6 A- mode ultrasound and pachymetry machine

7 Operating microscope

8 Phacoemulsification console

9 Phacoemulsification hand piece

10 Phacoemulsification Accessories

11 Photograph showing fixing of eye ball

12 Photograph showing the clear corneal incision using 2.8 mm keratotome

13 Photograph showing capsulorrhexis using Utrata capsulorrhexis forceps

14 Photograph showing hydrodisection using normal saline to release any

attachment between lens capsule and lens cortex

15 Photograph showing the introduction of Phaco tip through corneal incision to

sculpt and chop the cataractous lens

16 Aphakic eye - Post phacoemulsification

17 Loading of foldable IOL in to the IOL cartridge

18 Implantation of IOL by IOL inserter

19 Photograph showing the eye with artificial IOL implanted.

20 Photograph showing corneal ulcer positive for Flurorescein dye test

21 Ophthalmic surgical instruments

22 Photograph showing grid keratotomy

23 Photograph showing the multiple punctate keratotomy

24 Procurement of graft from superior bulbar conjuctiva

25 Photograph showing conjuctival graft on recipient site

26 Photograph showing eye with third eyelid flap.

27 Photograph showing eye with tarsorrhraphy

Fig no. Title

28 Age wise distribution of canine cataract cases of Group I

29 Sex wise distribution of canine cataract cases of Group I

30 Breed wise distribution of canine cataract cases of Group I

31 Classification of canine cataract cases of Group I

32 Stage of canine cataract cases of Group I

33 Occurrence of cataract cases of Group I

34 Photograph showing intraoperative hyphema

35 Photograph showing the slight corneal opacity after Phacoemulsification

36 Photograph showing clear cornea 15 days after Phacoemulsification

37 Age wise distribution of corneal ulceration cases of group II

38 Breed wise distribution of corneal ulceration cases of group II

39 Sex wise distribution of corneal ulceration cases of group II

40 Causative factor of corneal ulceration cases of Group II

41 Location of corneal ulceration cases of Group II

42 Photograph showing conjuctival hyperaemia in a dog with corneal ulcer

43 Photograph showing corneal opacity in a dog with corneal ulcer

44 Photograph showing central corneal ulcer in a dog

45 Photograph showing both dorsonasal and ventronasal ulcer in a dog

46 Photograph showing slight corneal opacity on 7th

post operative day undergone

multiple punctate keratotomy

47 Photograph showing complete healed cornea on 7th

post operative day

undergone grid keratotomy

48 Photograph showing scar and blood vessels on 15th

post operative day

undergone conjuctival grafting

49 Photograph showing scar on 30th

post operative day undergone conjuctival

grafting

LIST OF ABBREVIATIONS

Abbreviations Full form

@ At the rate

Mg Milligram(s)

Kg Kilogram(s)

BUN Blood Urea Nitrogen

AST Aspartate Aminotransferase

ALT Alanine Aminotransferase

D Diopter

AXL Axial Length

ACD Anterior Chamber Depth

LT Lens Thickness

PMMA Polymethylmethacrylate

IOL Intra ocular lens

CCT Central Corneal Thickness

IOP Intra Ocular Pressure

LIU Lens Induced Uveitis

et al et alia (and others)

Fig. Figure

PLR Pupillary Light Reaction

PCO Posterior Capsular Opacification

STT Schirmer‟s Tear Test

KCS Keratoconjuctivitis Sicca

GK Grid Keratotomy

MPK Multiple Punctate Keratotomy

BSS Balanced Salt Solution

MHz Megahertz

SE Standard error

% Percent

CHAPTER I

INTRODUCTION

The Eye is the only organ of vision in majority of living organisms which acts

as a biological camera and a window to the world (Dutta 2006). Living creatures find

their way in the environment through this biological camera with the aid of light

(Ramani et al 2005). Eye is a unique and highly complex organ in terms of structure

and function (Rooks et al 1985). It is a highly sensitive organ and its function may be

affected even with the mild insult to its homeostasis due to direct injury to the eye or

due to other local or systemic diseases (Whitley 1988). Good eye sight is an important

part of well being and a significant factor in retaining independence and quality of life

in companion animals (Warren 2004). There are various eye affections which are

responsible not only for decreased or complete loss of vision but can also lead to pain,

discomfort and unpleasant appearance of the patient (Hartly et al 2006). Most

common surgical ophthalmic affections reported are: corneal ulcer, cataract, iris

prolapse, proptosis, dermoids, glaucoma, cherry eye, keratoconjuctivitis sicca (KCS),

lid lacerations, neoplasms of globe and adnexa.

Cataract is one of the common ophthalmic diseases that mostly leads to

unilateral and more often bilateral blindness in dogs (Bigelbach 1994, Plummer et al

2007). Cataract formation is the most common abnormality of the lens. Significant

vision deficits can occur when the lens is opaque from cataracts (Martin 2010).

Cataract is classified by a variety of methods, but the most common method is based

on age, at onset, stage of maturity, location in the lens, and percentage of lens

involvement (Birchard and Sherding 1994). The only effective mean of treatment for

cataract is surgical extraction of diseased lens (Dziezyc 1990). The opinions on

cataract surgery have been changing continually with advancement of the procedure.

The success rate of cataract surgery has risen significantly during last decades,

especially thanks to development of more precise microsurgical techniques and with

introduction of phacoemulsification (Boldy 1988).

Cataract has many causes ranging from genetic to metabolic, nutritional to

toxic and/or traumatic to inflammatory. Cataract can develop secondary to intraocular

diseases such as glaucoma, luxation of the lens, chronic uveitis, progressive atrophy

2

of the retina, diabetes mellitus and other endocrine illnesses, traumas, and nutritional

conditions (Keil and Davidson 2001). Dogs over 13.5 years old usually have some

degree of lens opacity and metabolic alterations have been reported in the lens of

patients with cataract, such as those related to disorganization of lens proteins,

metabolic pumps, ionic concentrations and antioxidants (Davidson and Nelms 1998).

Regardless of the inciting or underlying cause, cataract result from abnormalities in

lens metabolism (Daniel et al 1984).

Diagnosis of cataract involves a good medical history along with thorough

ophthalmic examination. Electroretinography (Sims 1999) and ultrasonography (Van

Der et al 1993, Nasisse et al 1990) provide valuable information about the presence of

other ocular diseases and also assess the integrity and functionality of retina. Cataracts

can be most easily diagnosed by retro-illumination through a dilated pupil. Cataract

frequently begin as a small, focal opacity, which is incipient in nature. This usually

progresses to involve most of the lens. At this stage, the immature cataract obscures

funduscopic details (though a tapetal reflection is still present), and vision

deteriorates. As the cataract becomes completely opaque (mature), tapetal reflection

and vision are lost (Ofri 2007).

Surgical extraction represents the only method by which cataract can be

effectively treated (Williams 2004). Various surgical techniques have been used but

phacoemulsification with the implantation of an intraocular lens (IOL) is currently the

treatment of choice (Ruth 2003). Phacofragmentation and aspiration technique for

cataract removal is a type of Extra Capsular Cataract Extraction (ECCE) because it

removes the lens cortex and nucleus while leaving the lens capsule intact (Slatter

2002). In this procedure the lens is ultrasonically fragmented and aspirated through an

incision of about 2.8 mm with the advantage of smaller incision, less operating time,

there is lesser astigmatism, lesser complications and better recovery (Gelatt 1991).

The only disadvantages are the cost and learning curve of this procedure. IOL

implantation improves the optics of the aphakic eye and reduces the formation of

posterior capsular opacity (PCO) after surgery (Ameerjan 2005). However, IOL

decenteration or luxation can cause visual alterations or increase the risk of

postoperative complications. Another potential disadvantage of IOL implantation is

transient intraocular inflammation (Bras et al 2006).

3

In order to achieve post operative emmetropia, many researchers have

documented the diopter (D) of IOL optic in dogs with an IOL of approximately 41 D

being mainly used in canine cataract surgery (Davidson 2001). The most widely used

IOL material in veterinary practice is polymethylmethacrylate (PMMA) (Glover and

Constantinescu 1997). However, the use of various IOL materials such as acryl,

silicone and hydroxyethylmethacrylate (HEMA) optic IOL have also been reported

(Vajpayee et al 2005). Because acrylic and silicone lenses are flexible, they can be

implanted through a small corneal incision (Davidson 2001). This small incision

reduces the surgically induced astigmatism associated the use of a PMMA optic IOL,

which requires a corneal incision large enough to accommodate an 8-9 mm implant.

An acryl IOL with a squared edge is associated with a lower incidence of induced

posterior capsular opacification than other lens materials (Hollick et al 1997). This is

because acryl lenses have strong adhesion to the posterior capsule and the specific

optical design (squared) can inhibit the migration of lens epithelial cells into the optic

area.

The most common opthalmic disease reported in small animal practice is

corneal ulcer or ulcerative keratitis (Dorbandt et al 2015) Ulcerative keratitis can be

classified into superficial keratitis, deep keratitis, descemetocele keratitis, and

perforation keratitis, with reference to loss of corneal layers (Singh et al 2014).

Animals with corneal ulcers present clinical signs of epiphora, pawing,

blepharospasm, photophobia, and corneal opacity (Jhanji et al 2011). The variety of

underlying causes is limitless and includes numerous types of trauma (abrasion,

eyelash disease, foreign bodies, exposure due to prolapsed eyes, entropion), chemical

exposure (soap, acid, repellents), infection (bacterial, fungal, viral), metabolic

diseases (endothelial disease, keratoconjunctivitis sicca, hypoandrogenism) or

immune mediated diseases (immune mediated punctate keratitis) (Hansen and

Guandalini 1999). Corneal ulcers are classified according to depth, size, etiology,

presence or absence of infection and collagenase activity (Boisjoly et al 1989).

Despite early and proper treatment, corneal ulcers may progress rapidly and be

advanced at the time of presentation, requiring immediate and aggressive medical

and/or surgical intervention (Holmberg 1981). If the treatment or the diagnosis is

incorrect, the corneal ulcers may continue to enlarge and deepen or develop the

4

punctate keratitis or descemetocoele (Nasisse 1996). Most superficial corneal ulcers

heal rapidly without complication. Thus, only medical therapy using topical

antibiotics, mydriatic-cycloplegic agents and artificial tears are enough to prevent or

eliminate infection, alleviate discomfort, and facilitate healing (Slatter 1990; Kern

1990). Surgical therapy is considered for deep corneal ulcers, recurrent corneal ulcers

and stromal melting at initial presentation (Whitley 1991). Descemetocoele and

perforated corneal ulcers are considered surgical emergencies. Surgical treatment of

choice varies according to size and depth of the corneal defect (Sanberg et al 2012).

The most important features of treating deep corneal ulcers are to provide mechanical

support to the weakened cornea and stop further corneal destruction with sound

medical therapy (Boruchoff and Foulks 1990, Dawson and Sanchez 2015). Many

surgical techniques are reported, such as corneo scleral grafting (Slatter 1990),

conjunctival grafts (Dorbandt et al 2015 Boisjoly et al 1989), third eyelid flap

(Helper 1981, Gelatt 1991) and corneal transplantation (Severin 1995). Although third

eyelid flap technique is always easily performed in the treatment of superficial corneal

ulceration, it has some disadvantages such as corneal wound lacerate from the bulbar

side of the third eyelid during eye ball movement (Nasisse 1996). The techniques of

corneo scleral grafting and corneal transplantation are performed only occasionally

because of their serious complications and post operative management (Dawson and

Sanchez 2015).

In India, a few institutes are fully equipped and have trained veterinary

ophthalmologists to manage cases related to eye affections. The aim of this study was

to establish effective diagnostic procedures and treatment protocols that can restore

the proper vision of the animals.

Therefore, the present study was designed with the following objectives:

1. To evaluate the efficacy of Phacoemulsification procedure for cataract

removal and to study the feasibility of intraocular lens (IOL) implantation

procedure in dogs.

2. To establish suitable surgical protocol for the management of corneal

ulceration in dogs.

CHAPTER II

REVIEW OF LITERATURE

A comprehensive review pertinent to this subject is presented under the following

headings and sub headings.

2.1: Cataract

2.1.1 Aetiology and occurrence of Cataract

2.1.2 Pathogenesis of Cataract

2.1.3 Classification of Cataract

2.1.4 Diagnosis of cataract

2.1.5 Surgical treatment of cataract

2.1.6 Complications of cataract surgery

I Intra-operative complications

II Post-operative complications

2.2: Corneal ulcer

2.2.1 Incidence of corneal ulcer with respect to age, sex and breed

2.2.2 Diagnostic techniques for corneal ulceration

2. 2.3 Surgical management of corneal ulceration

2.1: Cataract

2.1.1 Aetiology and occurrence of Cataract

Donovan (1971) observed that congenital posterior sub capsular cataract

appears to be inherited as a result of simple autosomal recessive trait in Miniature

Schnauzer and Labrador retriever. Inherited cataract also occurs in American Cocker

Spaniel and the mode of inheritance is suspected to be simple autosomal recessive

trait.

Gelatt (1974) reported that several toxic substances can produce cataractous

lenticular changes when administered systemically. Certain hydrocarbons or

substituted hydrocarbons (Naphthalene and Dinitrophenol), salts of certain metals

(Thallium, Cobalt and Selenium), antimitotic agents, enzyme inhibitors and number

of drugs cause lenticular cataract.

Martin (1975) observed that commercial preparations of dinitrophenol

administered by various routes and various dosages have produced transient cataracts

of variable extent in dogs. It was further reported that experimental cataract have also

6

been produced in the dog following administration of 2, 6- dichloro-4-nitroaniline

(DCNA) (a fungicide), dimethyl sulfoxide (DMSO) and oral contraceptives.

Van Heyningen (1976) reported that dietary deficiency of amino acids and

vitamins may also lead to cataract. The absence of tryptophan may lead to abnormal

maturation of lens fibers so that cell nuclei do not disappear but are replaced by small

densely staining particles.

Gellat et al (1982) reported that heredity, metabolic diseases, senile changes,

trauma, nutritional deficiencies, toxins, drugs, radiation therapy, and inflammation

can all cause cataracts in dogs. Regardless of the inciting or underlying cause,

cataracts result from abnormalities in lens metabolism.

Whitley (1988) did a survey on canine ocular disorders and its breed

predisposition and enlisted breeds like Afghan hound, Australian Shepherd, Beagle,

Boston terrier, German Shepherd, Cocker spaniel, Doberman, Golden retriever, Grey

hound, Labrador, Lhasa Apso, Pointer, Poodle, Schnauzer, Siberian husky, Silky

terrier and Bull terrier susceptible to cataract formation.

Andley and Clark (1989) suggested numerous theories as the causes of

cataract. These include; oxidative damage caused by oxygen free radicals (hydroxyl

ions, hydrogen peroxide and ultraviolet radiation). Deficiency of antioxidants like

glutathione, catalase and ascorbate can result into cataractogenic changes in the lens.

As the lens ages the insoluble protein content in the lens increases more than the

soluble protein, which eventually leads to cataract development. Electrolyte

disturbances like increase in the Na+ and Ca

++ ion levels and decrease in K

+ ions

within lens due to decreased activity of Na+ / K

+ adenosine triphosphate pump in

epithelium may lead to development of cataract within the lens.

Engle and Spencer (1995) concluded that 60 – 80% of dogs with diabetes

mellitus develop cataract. It was further concluded that chronic anterior uveitis can

lead to cataract formation by altering the aqueous humor, which subsequently affects

lens nutrition. The majority of uveitis induced cataracts are inoperable because of

inflammation-induced intraocular tissue changes, such as synechia, secondary

glaucoma, and preiridial fibrovascular membranes.

Davidson and Nelms (1999) reported that cataracts may be congenital or

acquired at any age. Inherited or genetic cataracts are the most common kind of

cataract in dogs. Inherited mechanisms are suspected in more than 90 breeds of dogs.

7

Plummer et al (2007) stated that diabetic animals frequently develop cataracts

but can also have numerous other ocular problems, including uveitis, keratopathy,

retinopathy, and the effects of lipid derangements and systemic hypertension. As part

of the diffuse neuropathy affecting the sensorimotor nervous system of diabetics,

corneal sensation may be decreased and result in or complicate recurrent or indolent

corneal ulcers.

Ramani et al (2013) studied incidence of cataract in dogs and concluded that

the age group of 7 to 15 year had the highest incidence (50.22%) of cataract, followed

by 0 to 3 year age group dogs (19.5%) and 3 to7 year age group dogs had incidence of

30.80%. Regarding breed wise the incidence was highest in Spitz (36.49%), followed

by Non-descript (21.8%), Labrador (14.2%), German shepherd (6.06%), Cocker

Spinal and Rottwieler (5.2%), Terrier (3.3%) and other breeds (3.78%). It was further

concluded that incidence was more in males than in females.

2.1.2 Pathogenesis of cataract

Colitz et al (1999) speculated that the germinative region of lens epithelial

cells might have telomerase activity, and that disregulation of its activity might be

associated with cataractogenesis. It was investigated these hypotheses in lens capsule

specimens from normal and cataractous dogs and from cultures of canine lens

epithelial cells using standard assays for telomerase activity and telomere length.

Telomerase activity and telomere lengths were significantly greater in lens epithelia

from cataractous lenses when compared with normal lenses.

Salgado et al (2000) observed that an important complication of diabetes

mellitus in dogs is the development of intumescent (progressive) cataract. Cataract

developed in 75% diabetic dogs within 12 months. Diabetic cataract usually starts as

an equatorial vacuole and may progress rapidly to complete cataract within weeks,

months or a year of diagnosis.

Richter et al (2002) noted that in the diabetic animal, the enzymes responsible

for normal glucose metabolism become saturated; therefore, the sorbitol pathway, in

which the enzyme aldose reductase functions, metabolizes glucose. Excessive sorbitol

then accumulates in the lens, thereby increasing the osmotic state of the lens and

causing subsequent imbibition of water. Diabetic cataracts may develop acutely.

Cataracts that occur secondary to diabetes mellitus often imbibe so much water that

the lens swells and is referred to as intumescent.

8

Plummer et al (2007) stated that diabetic animals frequently develop cataracts

but can also have numerous other ocular problems, including uveitis, keratopathy,

retinopathy, and the effects of lipid derangements and systemic hypertension. As part

of the diffuse neuropathy affecting the sensory motor nervous system of diabetics,

corneal sensation may be decreased and result in or complicate recurrent or indolent

corneal ulcers.

Martin (2010) stated that hypocalcaemia associated with parathyroid

dysfunction, post parturient hypocalcaemia, and severe nutritional imbalances in the

young animal produces characteristic multifocal anterior and posterior cortical

opacities. These opacities do not seem to progress and thus do not produce signs of

blindness. The mechanism is probably through alterations of lens cell membrane

permeability from altered extracellular levels of calcium.

2.1.3 Classification of cataract

Cataract is the opacification of the lens and can develop in different parts of

the lens; therefore, one has to differentiate the types of opacities. For epidemiological

studies it is a prerequisite to classify the cataracts according to the age of animal at

onset, degree of maturation, causes, their localization within the lens as well as to the

size and intensity of the opacified area. It is also used to assist in predicting the

associated loss of vision and anticipated progression of the cataract.

I. Congenital cataract

Koch and Rubin (1967) stated that congenital cataract is present at the time

of birth, often bilateral and nuclear, and sometimes both nuclear and cortical. The

congenital cataract remains stationary for life and do not cause visual impairment. It

was further stated that most congenital cataracts are bilateral.

II. Juvenile or developmental or early onset cataract

Rubin and Flower (1972) reported that Juvenile cataract is one that develops

during early years of life (< 6 years of age). The cataract is hereditary in many breeds

e.g. Afghan Hound and Standard Poodle. It was further reported that other non

inherited causes of developmental cataract include trauma, diabetes, intraocular

inflammation and toxicity.

III. Senile or late onset or senescent cataract

9

Gwin and Gelatt (1985) found that senile cataract generally encompasses lenticular

changes in dogs over 6 years of age. These are simply associated with advanced age.

It occurs less frequently in dogs than in humans and may affect the nucleus as well as

the cortex. It was further reported that high incidence of canine cataract at the average

age of 10.58 years

IV. Stage of maturation

Davidson and Keil (2001) stated that stage of maturation refers to the

appearance of lens regardless of age of animal or the underlying problem causing

cataract. Not all the cataract progresses through each stage of maturation. Stage of

maturation has been considered important while determining whether a dog is a

candidate for surgery. The different types are given below:

Incipient cataract: This cataract represents very early lenticular changes and is not

associated with visual impairment. Usually less than 15% of lens is opaque.

Immature cataract: This stage is quite variable in its presentation. 10-99% of lens

may be affected but tapetal reflection will be present through some portion of lens.

Vision may be impaired to a variable extent but as the cataract progresses to maturity,

vision may be absent.

Mature cataract: In this stage there will be total or solid opacification of lens and

absence of tapetal reflection making the animal functionally blind. Normal lenticular

size and absence of fundic reflex are other characters of mature cataract.

Intumescent cataract: In this stage the lens may become markedly increased in size

due to imbibition of fluid. This enlargement of lens leads to the splitting and

separation of the lens suture lines with the resultant Y shaped fissure. Imbibition of

fluid may be quite rapid resulting in complete opacification. Vision may be impaired

to a variable extent.

Hypermature cataract: In this stage some of the lens fibers undergo liquefaction.

Occasionally during liquefaction of the cortex diffusion of liquefied cortical material

across the apparently intact lens capsule may occur. Leaking of liquefied cortical

material from the hypermature cataract result in a variable iridocyclitis. It occurs

because lens protein is immunologically foreign to the animal‟s immune system.

Morgagnian cataract: Here there is liquefaction of cortex with an intact nucleus. The

nucleus may drop or sink ventrally to the bottom of the capsular bag when the cortex

liquefies.

10

2.1.4 Diagnosis of cataract

Van der et al (1993) screened several canine patients presented for cataract

surgery with ultrasonography and discovered vitreous degeneration and retinal

detachment in eyes with hypermature cataract, while it was uncommon in eyes with

immature cataract. It was concluded that, ultrasonographic examination could detect

abnormalities of the posterior segment when opacity of the anterior segment precludes

complete ophthalmologic examination. It was further suggested that this was a quick

and easy procedure for screening dogs for retinal detachment prior to cataract surgery.

Ori et al (1996) performed diagnosis by B-mode two-dimensional

ultrasonography and reported hyper echoic changes in the anterior and posterior

cortices and nuclear pole in all 26 cataract affected eyes.

Strubble and Gelatt (1999) performed direct ophthalmoscopy in the patients

suffering from cataract and concluded that the technique is helpfull in differentiating

between mature and immature cataract

Silva et al (2010) performed A- and B-mode ultrasonography in cataractous

and non cataractous eyes of English Cocker Spaniel dogs and concluded that there

were non significant differences in measured parameters i.e. anterior chamber, lens

thickness and vitreous chamber between right and left eyes as well as in cataractous

and non cataractous eyes.

Martins et al (2011) performed ultrasonographic diagnosis of cataractous lens

in dogs and its correlation to phacoemulsification, and concluded that lens

echogenicity obtained by the computer-assisted ultrasonographic analysis were

correlated to the phacoemulsification time, such that the whiter the ultrasound image,

longer was the phacoemulsification time. The B-mode ultrasonography was also

helpful for the prediction of lens opacity location, but not predictive of lens hardness.

2.1.5 Surgical treatment of cataract

Magrane (1969) reported that success rate of 80% with extracapsular

technique where as it was 40% in cases of intracapsular method. It was also suggested

that the chances of success could be increased with the use of steroids pre and post

operatively.

Rooks et al (1985) performed a total of 240 extracapsular cataract extractions

on 214 dogs at the University of Illinois from 1968 to 1980. Overall success of the

surgery, as restoration of functional vision for at least 6 weeks after surgery, was '9%.

11

There was a significant difference in success rates between surgery on congenital and

juvenile cataracts as compared with surgery on diabetic and senile cataracts, the first

being 15% higher than the second. The success rate was 18% less for lensectomy with

concurrent iridectomy than for lensectomy without iridectomy.

Miller et al (1987) reported the success of phacofragmentation and aspiration

performed on 82 cases. After preoperative assessment of patient, medical

management was done by flunixin meglumine (1mg/kg) given 0.5 hrs. before surgery.

The eyes were topically treated with atropine, phenylephrine, corticosteroids and

antibiotics every 4-6 hrs. Ultrasonic power and aspiration were provided by a

handpiece and a 19 or 20G needle was attached to the irrigating hand piece extension

and connected to a bottle of warmed irrigation solution. The irrigating needle was

inserted at the limbus into the anterior chamber. A 2-3mm clear corneal incision was

made 1600

to 1800 from the irrigating needle using no. 65 Beaver blade. The flow rate

of the irrigating fluid was adjusted to maintain the anterior chamber. A cystotome

fashioned from a 25G needle was introduced and anterior capsulotomy was

performed. The lens was emulsified and aspirated while in the posterior chamber.

After aspiration, the incision was closed with an absorbable suture. Vision was

present immediately after surgery in 95% of these dogs.

Davidson et al (1990) compared postoperative results of 113 unilateral and 77

bilateral extracapsular cataract extractions (ECCE) in dogs. Restoration or

improvement of functional vision was achieved in 79.6% with unilateral extraction

and 85.7% with bilateral extractions following 4 to 6 weeks postoperatively. However

complications occurring 6 weeks to 9 months after lens extraction reduced the

surgical success rate in both the groups.

Whitley et al (1993) stated that cataract surgery in the dog could be highly

successful and rewarding technique for restoring vision to the cataract patient.

Coexisting ocular conditions such as kerato conjunctivitis sicca, uveitis glaucoma,

lens subluxation, and retinal disease were considered as contraindicated on to cataract

surgery. It was further stated that phacofragmentation was the most successful

technique in the dog however; post operative complications such as uveitis, hyphema,

glaucoma, capsular opacities, corneal endothelial damage, and retinal detachments

were recorded following the surgery.

12

Williams et al (1996) concluded that the success rates in canine cataract

surgery have increased markedly particularly as a result of the introduction of

phacoemulsification techniques and the reduction in the use of extracapsular cataract

extraction. It was further concluded that most post-operative complication in this

technique was uveitis followed by glaucoma.

Glover and Constantinescu (1997) stated that phacoemulsification has

substantially improved the success rate of cataract surgery in dogs, whereas the

development of artificial lens implantation has equally improved post operative visual

acuity.

Davidson et al (2000) compared the effect of different surgical cataract

extraction techniques on residual lens epithelial cell density and cell regrowth rates

and found that phacoemulsification with and without anterior and equatorial capsular

vacuuming led to less initial lens epithelial cell density in the capsular bag than extra

capsular cataract extraction.

Davidson and Keil (2001) stated that cataracts are readily amenable to surgical

intervention, with excellent results in terms of restoration of vision and replacement

of the cataractous lens with a synthetic one. If untreated, the cataracts cause

intraocular inflammation called Lens Induced Uveitis (LIU) that harms the eyes by

causing glaucoma. If the LIU is uncontrolled and glaucoma develops, cataract surgery

might not be possible.

Ruth (2003) studied phacoemulsification in the diabetic dogs and reported that

once the cataract had been diagnosed, 50% dogs developed the cataract within 6-12

months. It was described that phacoemulsification utilizes ultrasonic waves to break

up the cataract with simultaneous irrigation and aspiration of the lens fragments.

Following surgical removal of cataractous lens, vision was dramatically improved.

Kecova and Neaas (2004) summarized the evolution of phacoemulsification

technique and intraocular lens (IOL) implantation in dogs. Necessity of appropriate

patient selection for the surgery and precise surgical technique for successful outcome

of this procedure in dogs was emphasized. The history of cataract surgery, factors

critical for good outcome of the procedure, timing of surgery, pre operative

medication, phacoemulsification technique and types of implanted intraocular lenses

were discussed.

13

Pentlarge (2004) performed phacoemulsification in many cases of cataracts in

dogs. Observations showed that phacoemulsification and small incision allows

shortened surgical time, less tissue manipulation and less tissue trauma. This provided

for a more rapid physical rehabilitation and improved success. Another major

advantage was that cataract phacoemulsification caused little to no pain. It was

concluded that one or both eyes can have cataract surgery at the same time, even in

older patients. The success rate with phacoemulsification was very high.

Warren (2004) reviewed phacochop technique introduced by Dr. Kunihiro

Nagahara. Studies have shown that compared with four quadrants divide and conquer

technique, the phacochop technique uses less phaco- time and energy, significantly

reducing endothelial cell damage. Other advantages of phaco-chop included reduction

of zonular and capsular damage as forces were directed towards an apposing

instrument and phaco tip was kept in central „safe zone‟ in middle of pupil. This

technique was successfully adapted to canine phacoemulsification procedure.

Ameerjan (2005) explained recent trend in cataract management in canines

and mentioned that phacoemulsification utilizes high frequency ultrasonic vibrations

to fragment the lens into fine particles, which can be aspirated from anterior chamber.

It was reported that this technique had remarked advantage over extracapsular

extraction as it requires small incision, the surgery time is less and there is less post

operative uveitis and improved overall surgical result.

Hazra et al (2005) studied the procedure of phacoemulsification in dogs. Dogs

with complete and partial cataract were selected for removal of lens by

phacoemulsification. Standard pre operative preparations were carried out.

Phacoemulsification was performed with and without trypan blue assistance in

complete and partial cataracts, respectively. Vision was restored in all dogs following

standard post operative therapy, consisting of atropine eye drops, prednisolone eye

drops and antibiotics and steroid were given locally as well as systemically.

Phacoemulsification in dogs was carried out successfully and vision was restored.

Özgencil (2005) evaluated the results of phacofragmentation and aspiration

surgery for cataract extraction in dogs. Cataract surgery was planned on 41 ERG

positive eyes of 25 dogs of which 9 had unilateral and 16 bilateral cataracts.

Phacofragmentation and aspiration surgery was performed on 32 eyes of 20 dogs (and

ECCE was performed on 5 eyes of 5 dogs) of different breeds, sexes and ages. Vision

14

restoration and complications were evaluated. Mean age of 20 dogs was 7.3 years.

Stages of cataract were classified as mature, immature and intumescent. The mean

phacoemulsification time was 1.50 minutes in immature and mature cases. The

irrigation volume was 100 ml in intumescent and immature cases and 300 ml in

mature cases. Functional vision was established in 22.2% of mature eyes and 77.8%

in immature and intumescent eyes. The success rate for phacofragmentation surgery

was significantly better in immature and intumescent eyes.

Appeal et al (2006) performed a survey for evaluating clients‟ perception of

outcome concerning phacoemulsification surgery. It was found that 81% owners

reported the procedure as satisfactory method. However, they cautioned that surgical

risks and importance of post operative examinations, particularly in dogs undergoing

visual deterioration, must be conveyed to clients.

Wakanker (2006) conducted implantation of 41 D intraocular lens in 12 dogs

by both extracapsulr cataract extraction and phaecoemulsification. Intraocular lens

power was calculated using keratometer.

Yi et al (2006) evaluated the surgical outcome and complications of

phacoemulsification on 32 eyes of 26 dogs. It was concluded that along with foldable

intraocular lens implants, the central vision field of the dog was restored.

Brikshavana (2007) performed phacoemulsification on 25 eyes of 20 dogs and

a success rate of 96% was recorded as restoration of functional vision was noted in

24/25 eyes at the end of the study. Most common postoperative complications

recorded were uveitis and posterior capsular opacification.

Honsho et al (2007) studied the clinical events and variations in intraocular

pressure (IOP) that occur in endocapsular phacoemulsification technique were

compared to the modified extracapsular extraction technique during the intra

operative and immediate post operative periods on 24 eyes of 12 adult healthy

Mongrel dogs. In this study they concluded that Phacoemulsification technique

caused less corneal edema, less ocular discomfort and fewer postoperative

complications than the modified extracapsular extraction technique.

Jhala et al (2009) conducted studies on extra capsular lens extraction with

intraocular polymethyl-methacrylate lens (41 D, 6.5 mm optic and 17 mm haptic)

implantation on 14 eyes of 13 dogs with mature cataract, under propofol (5 mg/kg,

i.v.) anaesthesia. After 3 months of cataract surgery, restoration of ambulatory vision

15

was graded "good" in 57% cases followed by 'fair' in 29% cases and 'failure' in 14%

cases.

Mistry (2010) conducted a clinical study on 18 eyes of 17 dogs with cataract

using three surgical techniques viz, extracapsular extraction, manual small incision

and phacoemulsification for removal of cataractous lens with intraocular lens

implantation. Good results were obtained using extracapsular cataract extraction

(ECCE) in 66% eyes, small incision cataract surgery (SICS) technique in 83% eyes

and phacoemulsification in 100% eyes.

Kleiner (2011) performed cataract surgery using a one-handed

phacoemulsification technique followed by implantation of a foldable acrylic

intraocular lens in 180 dogs. He discussed that the advantage of not having the

blepharostat holding the eyes open is that there is no pressure in the globe and there is

less leakage from the incision and the anterior chamber is maintained. Finally

concluding that the success rate is very high and only a few complications were

observed and the sooner the surgery was done the better were the results and outcome

for the recovering of the vision.

Lim et al (2011) compared outcome for 77 cataractous eyes where each eye

underwent no treatment, topical medical treatment only, or phacoemulsification with

intraocular lens implantation and concluded that surgical extraction represents the

only method by which cataracts can be effectively treated. Although surgical success

rates have increased over time with refinements of surgical technique, surgical

success is not guaranteed. Surgery is considered to have failed when dogs develop

painful and/or blinding complications such as endophthalmitis, retinal detachment, or

glaucoma. Reported success rates, based on limited follow-up times, exceed 85% to

90%. Regardless of cataract stage, the chances of success were higher fore eyes

undergoing phacoemulsification than for eyes that received medical management

only.

Ramani et al (2011) performed bilateral cataract surgery in a dog by

phacoemulsification and concluded that phacoemulsification was a technically

demanding microsurgical procedure, involving less surgical time and easy visual

rehabilitation of cataractous dogs postoperatively.

Góes et al (2013) conducted a study on 25 dogs to investigate corneal

sensitivity after phacoemulsification surgery in dogs. In the study they found that

16

corneal sensitivity decreased after phacoemulsification surgery in dogs, which were

more evident at 30 days following the surgery.

2.1.6 Complications of cataract surgery

Improvements in surgical techniques, instrumentation and perioperative drug

regimes have markedly reduced the incidence of complications during and following

canine cataract extraction. Complications of cataract surgery may develop

postoperatively with any method of cataract extraction and may be related to

preoperative, intraoperative or postoperative events.

I. Intra-operative complications

Özgencil (2005) performed phacofragmentation and aspiration surgery on 32

eyes of 20 dogs (and ECCE was performed on 4 eyes and ICCE was performed on 5

eyes of 5 dogs) of different breeds, sexes and ages. It was reported that the most

important intraoperative complications seen in this study were anterior capsular

fibrosis, radial tear of anterior capsule and posterior capsular rupture-vitreous

prolapses, displacement of lens fragments into the vitreous cavity, cavitation bubbles,

miosis, iris herniation and corneal thermal injury observed in the mature and aged

dogs.

Vajpayee et al (2005) evaluated the risk factors of phacoemulsification and the

need of conversion to extracapsular cataract extraction. It was concluded that the

major risk factors were intraoperative pupillary miosis, posterior capsule rupture,

prolonged phaco time, posterior extension of the capsulorhexis, corneal thermal burn,

subluxation of the lens, and malfunctioning of the ultrasonic handpiece. Prompt

recognition of complications during phacoemulsification lead to timely conversion to

ECCE to achieve a good visual outcome.

Tuntivanich and Tuntivanich (2007) performed phacofragmentation and

aspiration technique without intraocular lens implantation in 26 mature cataractous

dogs. Several intra-operative complications occurred at different time points during

the surgery. Pupil constriction (miosis) occurred in 2 dogs immediately after cornea

was incised and for the second time after the lens had been partly sculpted. Blood in

anterior chamber (hyphema) was observed in one of the two dogs of which pupil had

become constricted during lens fragmentation procedure. Rupture of posterior lens

capsule caused vitreous prolapse in 2 dogs. It occurred while the phacofragmentation

17

tip was being applied at the posterior lens capsule for an attempt to remove the

remaining lens materials.

Honsho et al (2007) performed phaecoemulsification on twenty-four eyes

from 12 adult healthy mongrel dogs of both sexes, weighing 10 to 15kg. During

phacoemulsification, two cases of intraocular hemorrhage and one case of rupture of

the posterior capsule were observed.

II. Post-operative complications

Biros et al (2000) studied 220 cases (346 eyes) for 6 months to examine

factors responsible for the development of glaucoma post operatively. It was found

that mixed breed dogs as well as dogs with intraocular lens implants were at

significantly lower risk, compared with eyes without IOL placement. Further, it was

recorded that there was significantly higher risk of development of glaucoma

postoperatively in eye with hypermature cataract, compared with mature or immature

cataract.

Davidson et al (2000) compared the effect of different surgical cataract

extraction techniques on residual lens epithelial cell density and cell regrowth rates

and found that phacoemulsification with and without anterior and equatorial capsular

vacuuming lead to less initial lens epithelial cell density in the capsular bag than extra

capsular cataract extraction.

Lannek and Miller (2001) stated that recent improvements in the surgical

instrumentation and technique have substantially refined the art of the cataract surgery

in dogs and have also increased success rate at returning vision. However, post

operative development of glaucoma months to years after extraction remains a

common problem.

Collinson and Peiffer (2002) compared pathological complications arising

from methods of canine cataract surgery, manual extracapsular cataract on and the

more automated phacoemulsification and aspiration. Failures of manual

extracapsular surgical procedures were more commonly associated with post

operative synechia and glaucoma, compared with failures of phacoemulsification,

which, were more commonly associated with infection and rhegmatogenous retinal

detachments.

Adkins and Hendrix (2003) concluded that most common complications that

can occur after phacoemulsification include posterior capsular opacification,

18

persistent uveitis, endothelial degeneration and retinal detachments. Others include

ocular hypertension, glaucoma, corneal ulcers, and retinal detachment.

Bras et al (2006) opined that opacification of the capsule is one of the most

common post-operative complications after cataract surgery. Age and sex do not

influence significantly the occurrence of opacification of the posterior capsule, but

young animals and small and medium breeds have been seen to be the most affected.

Sigle and Nasisse (2006) determined common postoperative complications

and risk factors for development of postoperative glaucoma or failure to preserve

vision after phacoemulsification for cataract removal in 290 eyes of 172 dogs.

According to them the most common complication was mild posterior capsule

opacification. Prevalence of glaucoma increased with time, although it remained <

10% until after the 1-year follow-up period. Boston Terriers, Cocker Spaniels, Cocker

Spaniel–Poodle crosses, and Shih Tzus had increased risk of developing glaucoma.

Eyes with hypermature cataracts were more likely to develop glaucoma.

Yi et al (2006) concluded that the complications after phacoemulsification

were posterior capsular opacity (PCO) around the IOL, ocular hypertension, focal

posterior synechia, hyphema and corneal ulcer.

Honsho et al (2007) observed increase in post operative IOP, especially in the

case of phacoemulsification, that made pressure monitoring mandatory, as well as the

use of ocular hypotensive agents when the IOP exceeded acceptable limits.

Kim et al (2008) studied effectiveness of sutureless cataract surgery using a

clear corneal incision in dogs and compared it with sutured cataract surgery in terns of

refractive error, alteration in IOP, neovascularization on cornea. It was concluded that

clear corneal incision is an effective surgical method as it does not produce any

astigmatism, has no post operative effects on IOP and does not cause significant

corneal neovascularisation.

Joy et al (2011) conducted a clinical study on intra and postoperative

complications of cataract surgery with (34 eyes) or without (28 eyes) IOL was

conducted in 54 dogs with mature cataract under coaxial operating microscope.

Intraoperative complications included chemosis (06), haemorrhage from canthotomy

site (10), miosis (II), iris bulging (05) and vitreous prolapse (26). Postoperatively,

corneal oedema (27) and suture line opacity (57) were frequently observed. Suture

dehiscence (21) and subsequent iris prolapse was usually met in dogs with poor owner

19

compliance. Other complications were vaulting of IOL (in roomy eyes) (07), uveitis

(11), posterior capsular opacity (09) and retinal detachment (05).

Klein et al (2011) evaluated the postoperative complications and visual

outcomes of phacoemulsification in 103 dogs (179 eyes) and concluded that majority

of eyes were functionally visual (148 eyes, 82.7%) at the end of the study period.

Blindness was seen in 18 eyes (10.0%) with reduced vision in 13 eyes (7.3%) at the

final recheck. Postoperative ocular hypertension (22.9%), corneal lipid opacity

(19.0%), uveitis (16.2%), intraocular hemorrhage (12.3%), retinal detachment (8.4%),

and glaucoma (6.7%) were the most common postoperative complications seen in

eyes.

Lim et al (2011) studied cataract in 44 dogs (77eyes) and concluded that the

most common complications for dogs undergoing phacoemulsification in this study

were corneal disease (79.4%), intraoperative hyphema (55.9%), and glaucoma

(38.2%). They also concluded that deep corneal ulcers and keratoconjunctivitis sicca

(KCS) represented the majority of corneal diseases due to chronic use of ophthalmic

steroids, as is routine following cataract surgery, impairs corneal wound healing and

may predispose to the development of bacterial keratitis.

Góes et al (2013) conducted a study on 25 dogs to investigate corneal

sensitivity after phacoemulsification surgery in dogs. In the study it was found that

corneal sensitivity decreased after phacoemulsification surgery in dogs, which were

more evident at 30 days following the surgery.

Lu et al (2013) conducted a retrospective analysis on 118 non-diabetic dogs

and 119 diabetic dogs to study the incidence of keratoconjunctivitis sicca (KCS) in

diabetic and nondiabetic dogs after phacoemulsification. It was further concluded

those diabetic dogs were more likely than a non-diabetic dog to develop KCS after

phacoemulsification, especially in the small breeds.

2.2 Corneal Ulcer:

2.2.1 Incidence of corneal ulcer with respect to age, sex and breed

Holmberg (1981) studied the incidence of corneal erosions in dogs and concluded

that highest incidence was reported in Shih tzu (73%) followed by Boxers (20%).

Dogs with below 6 months of age were more predisposed towards the development of

corneal ulceration. The incidence was found more in males (80%).

20

Turner and Blogg (1997) reported different treatment techniques for the

management of corneal erosions in the dogs aged 11 months to 12 years with mean

age of 6.5 years. It was concluded that higher incidence of corneal ulceration was

found in pure breed Boxers (60%) followed by Corgicross (30%) and rest were mixed

pure breed dogs. The incidence was found more in males (80%) than in females

(20%).

Kim et al (2009) concluded that ulcerative keratitis was seen mainly in dogs

under 3 years of age (47%); disease frequencies in animals aged 3-6 years, 6-9 years,

and 9-12 years were 28%, 14%, and 9%, respectively among the total 32 dogs. The

Shih-Tzu (50%), Pekingese (25%), and Yorkshire Terrier (16%) showed the highest

ulcer frequencies. The Maltese Terrier, Pomeranian, and Golden Retriever frequencies

were all low, at 3%.

Venugopal (2011) studied corneal injuries in the dogs and concluded that main

cause of corneal ulceration in dogs was trauma. The incidence was found to be

highest in Pugs. It was further concluded that 79% dogs were below one year of age

and 14.9% were below 6 months of age.

Ramani et al (2012) reported incidence of corneal ulceration in dogs and it

was concluded that highest incidence of corneal ulceartion was found in the Pug

breed followed by Spitz, Non descript, Boxers and Labrador Retriver. The dogs

between the age group of 3 months to 3 years had highest incidence. The incidence of

corneal ulceration was found more in males than in females.

Ramani et al (2013) studied surgical bacteriology and grading of corneal ulcers in

dogs and concluded that corneal ulcers occurred to an extent of 67% in male dogs

and 33% in females. The breed wise incidence of corneal ulcers was higher in the Pug

(33.3%) followed by Labrador (16.6%) Spitz (12.5%), Doberman (8.3%), Mastiff

(8.3%), Boxer (8.3%). The age group between 1-3 years (50%) showed a higher

incidence of corneal ulcers followed by between 4-7 yrs (29.2 %),above 8yrs (20.8

%). Unilateral corneal ulcers were more common (75%). A higher incidence was

recorded in the right eye.

21

2.2.2 Diagnostic techniques for corneal ulceration

I Schirmer's Tear Test

Gelatt (1975) described Schirmer tear test (STT) as the most common test

which is performed by placing a 535 mm of Whatman filter paper no. 41 in

medioventral palpebral cul-de-sac of an unanesthetized eye for one minute and

recording the length of wetting of the strip.

Ludder and Heavner (1979) recorded decreased tear formation following

administration of atropine topically or systemically, alone or in conjunction with

general anaesthesia in dogs using STT strips.

Hollingsworth et al (1992) studied the effect of topically administered

atropine on tear production in the eyes of 19 dogs. It was concluded that that both

eyes had significant decrease in tear production and that was most marked at 120 min

after atropine instillation, then returned to base line values by 300 min after

instillation.

Kaswan (1995) reported that STT values can be influenced by topical

medications e.g. atropine decrease the tear production, topical solutions may falsely

increase values and fear experienced by animal increases sympathetic stimulation and

falsely decreases values.

Berger and King (1998) studied fluctuation and variation in canine tear

production from the results of daily Schirmer tear test without any topical

anaesthetics (STT-1), weekly STT-1 and STT with topical anaesthesia (STT-2)

conducted on healthy dogs. It was reported that fluctuations in STT values occured

both daily and weekly. The fluctuations were only biologically significant on a week

to week basis. There were significant differences between STT-1 and STT-2 values in

dogs. The results also indicated that weight has significant effect on STT values, with

higher values measured in dogs having more body weight.

Bowersox and Criox (2001) reported that clinically normal animals may have

STT values as low as 5 mm/ min, and suggested that the interpretation of the values

should be done in light of clinical signs.

Kotani (2001) undertook studies on estimation of tear production rate by

Schirmer tear test (STT) in dogs. STT values for adult canine were reported as

21.3 ± 3.8 mm/min, 18.89 ± 2.62 mm/min and 18.64 ± 4.471 mm/min respectively. In

22

this study, STT measurements of 11–14 mm/min were considered moderately low

and readings of equal to or less than 10 mm/min were considered low.

Lin and Wu (2002) performed Shermir”s tear test on 50 dogs suffering from

various corneal affections. On ophthalmic examination, bilateral involvement of eyes

was observed in 30 dogs and unilateral involvement in 20 dogs; the bilateral ones

tend to have more severe clinical lesions. Among the 17 bilaterally affected dogs with

STT readings, 10 eyes had mild or early KCS (STT: 11-14 mm/ min), 4 eyes with

moderate KCS (6-10 mm/ min) and 20 eyes with severe KCS (0-5mm/ min). Among

the 10 dogs with unilateral disease, 6 eyes had moderate KCS (6-10 mm/ min) and 4

eyes had severe KCS (0-5 mm/min).

Thangamuthu and Varshney (2002) conducted study to generate base line data

on tear production in dogs and to see the effect of sex, age, body weight and breed on

tear production. Overall STT values for left and right eyes were 22.54 ± 0.41mm/ min

and 22.62 ±0.41mm/ min respectively. Tear production pattern of right and left eyes

was almost similar. Sex, age, body weight and breed did not significantly influence

the STT values.

Hartley et al (2006) subjected 100 dogs of different age to STT every 2 hours

during the day in randomly chosen eye. It was observed statistically significant effect

on tear production of time of day and age up on the STT measurements. Mean STT

values taken at 10.00 a.m. were 0.7 mm lower than the values taken at 4.00 p.m.

(0.04mm). The mean STT decreased by 0.4 mm for every one year as age increased

(P=0.007). It was further concluded that tear production decreases with age in the

normal dog and greatest difference was between 10.00 a.m. and 4.00 p.m.

II Fluorescein dye test

Maurice (1967) stated that topical fluorescein can be used in veterinary

ophthalmology to detect the corneal epithelial defects, to test nasolacrimal duct

patency and to assist in the measurement of intraocular pressure with the Goldmann

and Draeger tonometers.

Felchle and Urbanz (2001) reported that fluorescein dye will not penetrate the

intact lipophllic corneal epithelium, but when corneal defects are present the

fluorescein will stain. The fluorescein stained cornea can be examined under blue

filter of the ophthalmoscope in a dark room.

23

Lin and Wu (2002) diagnosed 110 cases of ulcerative keratitis in 90 dogs and

20 cats. The diagnosis and assessment of ocular lesions were based on clinical signs,

slit lamp biomicroscopy, fluorescein staining, STT, examination of nasolacrimal

system, and microbiological cultures.

Moore (2003) diagnosed chronic corneal epithelial defects or indolent corneal

ulcerations from its classic appearance with the use of fluorescein stain which borders

the epithelial lip.

Ollivier (2003) stressed the use of magnification system, fluorescein dye,

corneal cytology and culture for diagnosis of corneal diseases especially ulcerative

keratitis at an early stage of the disease in dogs and cats.

2.2.3 Surgical Management of corneal ulceration

Dice (1981) stated that direct blood supply to the wound provided by

conjunctival flap is very beneficial as serum contain collagenase inhibitors, which

counteract collagenase produced in necrotic and infected corneal tissues. Helper

(1981) stated that conjunctival flaps also raised the temperature of cornea and

facilitated healing by increasing corneal cellular metabolism.

Holmberg (1981) studied the use of conjuctival pedicle grafts for the

treatment of corneal perforation in horses and concluded that conjuctival pedicle

grafts helped in healing of corneal ulcers by preservation of corneal integrity,

minimizing lesions incompatible with functional vision and replacement of lost

corneal tissue. Increased blood supply to the healing cornea was an added benefit not

obtained by other procedures such as lamellar corneoscleral transposition or full

thickness corneal graft.

Stadsvold (1995) studied different treatments for corneal ulcers in 61 eyes

from 60 animals (53 dogs, 5 cats, 2 rabbits). The cornea of all eyes was debrided to

remove loose epithelium. This was followed by gluing, cauterizing with 90% phenols,

covering with a third eyelid or conjunctival flap or a combination of these methods or

keratotomy. Keratotomy was the most effective with complete healing in 100% of 27

treated eyes. Adequate anti-inflammatory therapy was indicated when corneal

epithelium becomes intact.

Turner and Blogg (1997) studied the effect of multiple striate keratotomy: a

treatment for corned erosions caused epithelail basement membrane disease and

concluded that multiple striate keratotomy was a safe, effective and well tolerated

24

technique for the treatment of persistent corneal erosions thought to be caused by

corneal epithelial basement membrane disease.

Stanley et al (1998) performed superficial keratectomy, grid keratotomy and

debridement by sterile cotton swab and concluded that superficial keratectomy and

grid keratotomy were highly successful techniques for the treatment of persistent

corneal ulcers.

Hansen and Guandalini (1999) used frozen corneal lamellar grafts and

nictating membrane flaps in dogs and cats to repair deep corneal ulcers. It was

concluded that frozen lamellar corneal graft technique was safe and restored the

optical function of the cornea.

Laus et al (1999) used bilateral lamellar keratoplasty and conjuctival pedicle

graft in dogs and it was concluded that the both the techniques were found

satisfactory for the managemant of deep corneal ulcer however in conjuctival graft

technique was found much easier and less time consuming than bilateral lameller

keratoplasty.

Croix (2001) compared mean healing times after debridement with grid

keratotomy and superficial keratectomy in cats with non healing ulcers and concluded

that brachycepahlic cats appear to be more predisposed to development of non healing

corneal ulcers. It was further concluded that superficial debridement and grid

keratotomy decreased the mean healing time of non healing ulcers.

Hamor (2003) reported that third eye lid flap provided a readily available

protective bandage for cornea in any condition where corneal coverage support or

protection is required. Third eye lid may be sutured with upper eye lid or with

superior bulbar conjunctiva particularly in brachycephalic breeds.

Hollingsworth (2003) described different procedures for corneal surgery

which include cornea1 laceration repair, conjunctival pedicle graft, tarsoconjunctival

island graft, advancement graft, total conjunctival graft, frozen tectonic cornea1 graft,

porcine small-intestine submucosa graft, and superficial keratectomy. The conjuctival

pedicle graft technique was found much superior that the other techniques.

Moore (2003) concluded that chronic corneal epithelial defects were most

common refractory ulcerations in veterinary patients and proper diagnosis and

treatment procedures should be adopted for these corneal ulcerations. It was further

concluded that recommendations should consist of identifying and treating the

25

underlying cause that may stimulate epithelization and adhesions of corneal

epithelium.

Soontornvipart et al (2003) performed conjuctival pedicle grafts in dogs and

cats for the treatment of deep corneal ulcers and the success rate was as high as

93.18%. The success rate did not significantly depend on breed, age and sex of the

patient, size and depth of corneal lesion, selection of suture material and antibiotics,

but depended significantly on surgical techniques and type of technique performed.

Bentley (2005) reported the occurrence of spontaneous chronic epithelial

defects (SCCEDs) especially in middle aged dogs. On histopathology it was found

loss of corneal epithelial basement membrane and formation of a superficial,

acellular, hyalinised zone in the stroma was found. It was further concluded that

epithelial debridement, anterior stromal puncture, grid keratotomy, and superficial

keratotomy were the most common treatment options applied to these defects.

Cullen and Grahn (2005) performed lamellar keratectomy and conjuctival

graft in a female Shis Tzu dog having corneal foriegn body and it was observed that

lamellar keratectomy followed by conjuctival graft was found ideal surgical

technique which helped in the corneal healing within a short period of time.

Brunott et al (2007) performed grid keratotomy for superficial non healing

ulcer in horses and concluded that horses generally responded well to grid

keratotomy. The healing time, which was known in seven cases, averaged 8.4 days.

Grid keratotomy was found to be an appropriate method for treatment of superficial

non healing corneal ulcers in horses. The procedure was considered simple to perform

and generally induced a rapid and uncomplicated healing of the cornea.

Janssens (2007) performed punctate keratotomy, grid keratotomy, superficail

keratectomy amd debridement techniques in dogs having indolent corneal ulcers. It

was concluded that grid keratotomy and superficial keratectomy were found better

surgical tehniques in which healing of ulcers occured rapidly and within shorter

period of time. The main disadvantage with punctate keratotomy was greater risk of

deeper damage to the cornea. The success rate was slightly lower than that with the

linear keratotomy, perhaps as a result of the reduced stromal surface area exposed

with punctate wounds as compared with linear.

Jones et al (2007) reported grid keratotomy on eye of llama. It involved

incision of the cornea which extended into the healthy corneal stroma to encourage

26

adherence between the epithelium and the stroma. Grid keratotomy combined with

epithelial debridement decreases healing times for indolent ulcers.

Maggs (2008 a) demonstrated that opacity resulting from uncomplicated

stromal wounds can be limited by the supervised use of corticosteroids, provided,

infection has been controlled, and an epithelial covering as demonstrated by

fluorescein has been established. Topical corticosteroids limit opacification by

inhibiting fibroplasia, decrease vascularization, reduce pigmentation and improve

final transparency.

Maggs (2008 b) stated that there is no blood vessel in the normal cornea but

suggested that vascularisation of the cornea may be induced by differentstimuli

including stimulated lymphocytes or their elaborated lymphokines. Conjunctival flaps

were indicated for repair of large defects for covering the recurrent corneal erosions

and for treatment of deep or progressive ulcers.

Kim et al (2009) studied the different treatment protocols in dogs having

corneal ulcers and concluded that superficial corneal ulcers treated with medication

took 5.1-13.4 days to heal and nine eyes with deep corneal ulcers, treated with

conjunctival flap construction, took 28.4-40 days to heal. It was concluded that

conjunctival flap construction was an effective treatment for deep corneal ulcers. The

recovery rate from superficial corneal ulcers was 100% and that from deep corneal

ulcers 55%.

Vongsakul et al (2009) used canine amniotic membrane (AM) transplantation

in conjunction with a third eyelid flap to promote healing of created deep corneal

ulcers. The average time to complete corneal epithelialization in the eyes receiving

the AM transplantation in conjunction with the third eyelid flap was 7.33±0.21 days

which was significantly shorter than the average time of 9.17±0.31 days observed in

the eyes receiving only the third eyelid flap.

Asghari and Gharachorou (2011) studied role of antibiotic adminstration in

the treatment of corneal ulcers in dogs. In the study 54% of the dogs were cured with

antibiotic adminstartion, 28% needed corneal surgery and 18% of the dogs underwent

evisceration due to perforation of the cornea. It was concluded that most of the

superficial bacterial corneal ulcers can be treated with proper adminstration of the

broad spectrum antibiotics while as deep corneal ulcers need corneal surgery such as

grid keratotomy and superficial keratectomy.

27

Hvenegaard et al (2011) studied that indolent ulcers are superficial corneal

ulcers secondary to several changes on the corneal surface. These are frequently

observed in middle-aged Boxer dogs, caused pain of acute onset and required

appropriate treatment. Results demonstrated that proteinase inhibitors were the most

often prescribed medication, and its administration did not interfere on the healing

rate, as well as observed in dogs that received 1% atropine, antibiotics and anti-

inflammatory drugs. It was concluded that debridement/cauterization, administration

of proteinase inhibitor eye drops, prophylactic topical antibiotics and oral vitamin C,

should be considered as an effective clinical management for indolent ulcers in

Boxer dogs.

Jhanji et al (2011) observed that corneal perforation results from a variety of

infectious and noninfectious disorders and require prompt management. Small

perforations respond reasonably well to corneal gluing techniques, peripheral

perforations can be best managed with a partial conjunctival flap keratoplasty.

Sarbani and Himangshu (2011) performed Grid Keratotomy for treatment of

atypical Indolent Corneal ulcers in a Boxer dog and concluded that grid keratotomy

was safe and effective in superficial indolent ulcers refractory to topical antibiotic

treatment.

Grad (2012) performed conjuctival graft in a Pug having desmatocele. It was

observed that an extended care was needed post opeartively in order to achieve good

results. It was further concluded that conjuctival grafts was a good surgical technique

in case of deep corneal ulcers and desmatocele.

Singh et al (2014) compared different surgical techniques for the management

of corneal ulcers in dogs and concluded that grid keratotomy and third eye lid flap

techniques were effective in surgical management with minimal complications in both

superficial and deep ulcers as compared to punctate and conservative treatment.

CHAPTER III

MATERIALS AND METHODS

The present study was conducted on 48 clinical cases of eye affections in dogs

diagnosed for cataract (n=27) and corneal ulceration (n=21) at Department of

Veterinary Surgery and Radiology, GADVASU, Ludhiana from the period August

2013 to November 2015.

The clinical cases were divided in two groups i.e. Group I (n=27) that

comprised of canine cataract cases and Group II (n=21) consisted of canine corneal

ulcer cases. Group I was further sub divided according to the surgical management in

to Group I A (n=5) in which rigid Polymethylemethacrylate (PMMA) lens was

implanted after phacoemulsification and Group I B (n=22) in which foldable square

edge acrylic lens was implanted after phacoemulsification. Group II was also sub

divided in to Group II A (n=8) in which corneal scarification technique was adopted

(Grid keratotomy (n=4) and Multiple punctate keratotomy (n=4)) and Group II B

(n=5) in which both corneal scarification and conjunctival grafting was used and

Group II C (n=8) in which only conjunctival grafting was used (Table 1). The animals

for the purpose of sub grouping were selected randomly after complete ophthalmic

examination.

Table 1: Brief outline of the study conducted on cataract and corneal ulceration

cases in dogs

Groups Sub groups Surgical Technique used.

Group I

(n= 27

of 23 dogs)

Group I A

(n=5)

Implantation of rigid

polymethylmethacrylate lens after

phacoemulsification.

Group I B

(n=22)

Implantation of foldable square edge

acrylic lens after phacoemulsification.

Group II

(n=21

of 21 dogs)

Group II A

(n=8)

Corneal scarification by

Grid keratotomy (n=4) and

Multiple punctate keratotomy (n=4)

Group II B

(n=5)

Corneal scarification and conjuctival

grafting.

Group II C

(n=8)

Conjuctival grafting.

29

3.1 GROUP I (CATARACT)

3.1.1 Diagnostic equipments: Essential diagnostic equipment and eye solutions

which were used in ophthalmic examination and diagnosis were panoptic direct

ophthalmoscope1 (Fig1) head mounted indirect binocular ophthalmoscope

2 (Fig 2), 20

D lens for indirect ophthalmoscopy, Tonopen-Vet tonometer 3, Fluorescein dye

strips, Schirmer‟s tear test strips (Fig3), dilating agent tropicamide4 1% and local

anaesthetic proparacaine5 0.5%

3.1.2 Detailed Ophthalmic Examination.

Pre operatively, all the animals in group I underwent detailed ophthalmic

examination using following tests/criteria.

3.1.2.1 Examination of eye - A thorough examination with confirmation of the

diagnosis of cataract by complete ophthalmic examination included Schirmer‟s tear test,

Fluorescein dye test, Applanation tonometry, and Ophthalmoscopy. Ocular A – mode

ultrasonography and Pachymetry were also done for the ocular biometric analysis.

3.1.2.2 History - The history pertaining to the onset of blindness (sudden/gradual),

duration of vision loss, details of earlier treatment (if any) of the animal were

recorded.

3.1.2.3 Nature of Blindness - History pertaining to visual acuity during day and night

was obtained.

3.1.2.4 Tests of Blindness - Following tests as per the standard procedures were

performed to ascertain visual acuity (Ofri, 2008).

I Menace Response (MR) – A normal menace response was evident as eyelid

closure when the examiner stimulated the eye in a visually “threatening” way,

usually by waving a hand in front of it. Also known as blink reflex; involves optic

(second; afferent) and facial (seventh; motor) nerves - subcortical reflex from

sudden stimulation of visual system (such as foreign body moving toward eye) -

leads to reflex closure of palpebral fissure and turning of head away from the

stimulus.

1 Welch Allyn: State Road, New York, U.S.A 2 Welch Allyn: State Road, New York, U.S.A 3 Richeret-TM: Depew, New York, U.S.A 4 Tropac: Jawa Pharmaceuticals Pvt. Ltd. New Delhi, India 5 Paracain: Sunways India Pvt. Ltd. Mumbai, India

30

II Pupillary Light Reflex (PLR) –A pen focal light source (pen torch) was projected

into the eye and resultant constriction of pupil was recorded as direct pupillary

reflex. Both direct and consensual (constriction of contra lateral pupil) PLRs are

detected. The pupil under the direct light stimulation was slightly smaller than the

opposite consensual pupil size. This was considered as a normal or satisfactory

pupillary reflex.

III Dazzle or Photic Blink Reflex - This test was conducted by directing a direct

beam of light at the ocular fundus and observing the positive blink reflex.

IV Maze Test - Placed the animal on the floor with various obstacles in their

way. Assessed their ability to navigate in both normal room light as well as in

dim light.

V Tapetal Reflex – It is the reflex from the tapetum obtained by directing direct

beam of light.

VI Palpebral reflex: It was performed by tapping the lateral and medial canthus of

the eyes to elicit a blink response, which is also present in apparently blind

animals. It determines the integrity of facial and maxillary branch of trigeminal

nerve and auriculopalpebral branch of facial nerve through the pupil. A greenish

reflex indicates positive tapetal reflex.

VII Cotton Ball Test: The ability of the dog to detect and follow a moving object, in

this case a cotton ball thrown or moved across its field of view. The ability to

follow the path of motion of the cotton ball was considered based on the head and

eye movements of the animal.

3.1.3 Special Diagnostic Procedures used by (Moore, 2003) were used as following:

3.1.3.1 Schirmer’s Tear Test – It was performed to measure the tear production,

using sterile, absorbent Whatman No.41 filter paper (5mmx 40mm). The strip was

placed in the medioventral to lateral third of the palpebral conjunctival fornix for one

minute (Fig 4). The strip was removed from the eye and tear wetting was compared to

millimeter scale. The value was graded as - Normal (15 – 25mm/min).

3.1.3.2 Fluorescein Dye Test - Corneal staining was done with the help of

commercially available fluorescein strips for detecting corneal epithelial defects and

corneal ulceration. Use of fluorescein strip: Remove the fluorescein strip from

packing. Place 1-2 drops of sterile eye wash solution onto the strip and tilt it to allow

31

Fig. 1: Panoptic Direct Ophthalmoscope

Fig. 2: Indirect ophthalmoscope with 20 D Lens

Fig. 3: Fluorescein dye strips and Schirmer’s

Tear test strips

31

the stain to drain into the eye. Wash the excess stain with eye wash solution and

examine for stain uptake. Normally a healthy cornea does not stain. Any epithelial

defect in the cornea will stain green with fluorescein dye.

3.1.3.3 Tonometry - This was used for estimation of intraocular pressure. After

applying topical anaesthetic proparacaine 0.5%, the Tonopen was switched on and

after the beep, the instrument was held like a pen and was tapped on the eye very

gently (Fig 5), each tap gives a “click” sound, after 4 taps, a beep sound is heard

which gives an average reading of the 4 taps as intraocular pressure in mm of Hg. It is

important that the probe of Tonopen is very gently touched on the cornea without any

force.

3.1.4 Ophthalmoscopic examination:

It was done with panoptic ophthalmoscope and/or direct ophthalmoscope for

the examination of the interior of eye.

3.1.4.1 Use of Direct ophthalmoscope:

Direct ophthalmoscopy is done after instilling topical 1% tropicamide in the

eye to be examined. The help of an assistant is needed for preventing the movement

of patient. The assistant held the head of the dog steady by keeping one hand below

the angle of lower jaw and with the other hand the eyelids were held apart with the

fingers against the lateral side of the eye ball to prevent movement. The instrument

was held as close as possible to the observer‟s eye. In the first instance at about 10 to

12 inches from that of the patient‟s eye, a greenish or yellowish tapetal reflex was

seen and there was a general view of the refractive media. For detailed examination,

the instrument was brought as close as possible to the patient, thus giving maximum

magnification.

The lenses were rotated to obtain a good picture of fundus consisting of optic

disc, tapetum lucidum and tapetum nigrum. As dog is normally myopic, these

structures are seen at -3 to 0 setting. The vitreous opacities are seen between -3 to

+8D, the crystalline lens between +8D to +12D and iris, anterior chamber and cornea

between +12D to +20D.

3.1.4.2 Use of Panoptic Ophthalmoscope

This instrument is very similar to the direct ophthalmoscope in the working,

the eye cup is placed on the orbital rim of the patient‟s eye, and the observer keeps its

32

eye at the other end, holding the ophthalmoscope from the handle, while rotating the

lens setting using the thumb.

The field of view is much larger (25o of whole fundus) as compared to direct

ophthalmoscope (5o) but the magnification is lower than that of direct

ophthalmoscope.

3.1.4.3 Indirect Ophthalmoscopy - Fundus was viewed indirectly using a convex

lens (20D) which was placed between the patient's and the examiner's eyes (bright

focal light source). Optic nerve was evaluated for size, shape, colour and elevation

/depression. Retinal blood vessels were observed for size, congestion and

heamorrhage, and also for the hypo/ hyper reflectivity of tapetum.

3.1.5 Ocular biometric analysis: It was done by A-mode ultrasonography and

Pachymetry

3.1.5.1 A - mode Ultrasonography: A mode ultrasonography was done to determine

the axial length of the globe (from cornea to retina). The instrument6 (Fig 6) provides

a line with spaced irregularities representing echos from different densities of ocular

tissues and these echoes can be observed on a graphic display as a two dimensional

waveform with spikes that are related to the positions of the interfaces. The cornea of

the prospective eye was anaesthetised using 0.5% proparacaine topical eye drops,

applied twice at intervals of 5 min. The transducer was placed in contact with the

cornea and aligned in the visual axis of the central cornea in automatic mode to obtain

the readings. when alignment of probe along the visual axis is met properly two high

spikes representing the anterior lens and posterior lens interfaces, along with a strong

spike representing the retinal interface. The frequency range of A-scan equipment

may extend from 6 to 15 MHz. The actual ocular parameters including axial length

(AXL), anterior chamber depth (ACD), and lens thickness (LT) were measured.

3.1.5.2 Pachymetry: Pachymetry is the measurement of the corneal thickness in the

living eye. Ultrasonic Pachymetry is the most accurate in vivo method currently

available to measure corneal thickness. The time required for ultrasonic energy to

traverse the cornea was recorded, and thickness was calculated by the use of a preset

constant for velocity (1630m/sec.) of sound through the cornea. It was done in same

way as the A- mode ultrasonography was done. The transducer was put on cornea

6 Pac Scan Plus: Sonomed 1979. Marcus Avenue Lake Success, New York – U.S.A

Fig. 4: Photograph showing Schirmer's Tear

test in a dog

Fig. 5: Photograph showing measurement of

IOP using Tonopen in a dog

Fig. 6: A- mode ultrasound and pachymetry

machine

Fig. 7: Operating microscope

Fig. 8: Phacoemulsification console

33

after topically instilled anaesthetic on eye. It is easier to perform than A – mode

ultrasonography as it offers the advantages of reproducibility, high accuracy, ability to

take measurements anywhere on the cornea, not dependent on patient fixation, and

ease of use. Pachymetry gives indication about health of cornea.

3.1.6 Instrumentation

For operative area inbuilt light source from coaxial operating microscope7 (Fig

7) was used. Single holed white cotton drape covered with disposable adhesive plastic

drape was used. For Phacoemulsification, equipment included 2.8 mm keratome, 15°

lance tip blade, chopper, capsulorhexis forceps, lens dialer, visoelastic materials for

maintaining anterior chamber, trypan blue dye for staining lens capsule,

phacoemulsification unit (peristaltic pump) were used.

3.1.6.1 Phacoemulsification unit

The unit consists of a phacoemulsification console and its accessories.

a. Phacoemulsification console: It employs a versatile microprocessor control of all

primary functions (Fig 8). It utilizes an ultrasonic frequency. It has a foot control

offering linear as well as on/off functions. The screen display provides the user with

essential feedback and instructions concerning operation and functions. The basic

principle of phacoemulsification is the use of electrical energy for the production of

ultrasonic waves through piezoelectric crystals present in the transducer. The

vibration of the phacoemulsification needle at these ultrasonic frequencies serves to

break down (emulsify) the lens material. After the conversion of the lens material into

an emulsate, the fluidic system of the machine removes the emulsate and replaces it

with balanced salt solution (BSS).

The unit consists of the following accessories

b. Phacoemulsification hand piece: It has a right-hand threaded needle, irrigation

fitting and aspiration fitting (Fig 9).

c. Irrigation/aspiration hand piece: It is used for cortical clear up after

phacoemulsification and aspiration of the nucleus.

d. 300 phaco needle: The Phaconeedle is made of titanium.

e. Needle wrench, blue silicon sleeve, test chamber: The needle wrench is used to

tighten the titanium needle onto the phacoemulsification hand piece. The test chamber

7 Shin Nippon OP-2, Ohira Co. Ltd- Japan

34

is used during calibration of the machine and the silicon sleeve is used to cover the

phacoemulsification needle in order to prevent heat dissipation into the surrounding

medium (Fig 10).

f. Foot controls: The left right foot switch provide on/off control of the reflux function,

vitreous cutting and phacoemulsification procedures. The top foot switch provides on off

control for bipolar coagulation. As the central foot pedal is pressed the pedal position will

be detected to provide adjustable control of certain features. The foot pedal provides

activation of all functions of the phacoemulsifier. It has four positions. Position 0 is the

rest position in which the system is not active but ready to be so. The pinch valve opens

as the pedal position is moved from 0 to 1 providing the infusion of balanced salt solution

through the hand piece. With passage to position 2, the aspiration pump is also activated.

When the pedal is in position 3 it controls the linear and fixed phacoemulsification power.

3.1.7 Pre-operative Procedures

3.1.7.1 Preoperative medication

All dogs received topical antibiotic Gentamicin8

, 1% Tropicamide and

Atropine 9 eye drops as mydriatic and 0.5% Povidone Iodine

for ocular antisepsis 2-3

times prior to surgery. A single intravenous injection of Cefotaxime 10

@ 25 mg/kg

body weight was given to eliminate ocular infection.

3.1.7.2 Anaesthesia

All the dogs in group I were premedicated using combination of

Glycopyrrolate11

@ 0.01mg/kg +Acepromazine maleate12

@ 0.05 mg/kg +

Butorphenol13

@ 0.2 mg/kg intramuscularly. Induction was performed using

Diazepam14

@ 0.5mg/kg body weight and Ketamine15

@ 5mg/kg body weight

combination intravenously “to effect” followed by a maintenance with 1 to 2%

Isoflurane 16

.

8 Genticyn:Allergen India Pvt. Ltd, Pithampur (M.P)-India

9Atro: Intas Pharmaceutical Ltd.Ahmedabad Gujrat-India

10 Taxim: Alkem Laboratories, Mumbai, India

11 Pyrolate: Neon Laboratories Ltd, Mumbai, India

12 Ilium-Acepril-10: Troy Laboratories Pty Ltd, Australia 13

Butodol: Neon Laboratories Ltd, Mumbai, India 14

Lori: Neon Laboratories Ltd, Mumbai, India 15

Aneket: Neon Laboratories Ltd, Mumbai, India 16

Forane: Aesica Queenborough Ltd, UK

Fig. 9: Phacoemulsification hand piece

Fig. 10: Phacoemulsification accessories

35

3.1.8 Positioning and draping of the patient

The dogs were placed in lateral recumbency with the affected eye placed

dorsally and head was positioned by placing soft padding under the nose bridge, so

that the nose is straight up or slightly away from the eye intended for surgery. Eye

was draped with a light coloured drape with a hole of about 5 cm in diameter in the

centre. Sterile drapes covered the rest of the dog‟s body to avoid contamination.

Surgery was performed by the surgeon sitting on the dorsal side of the patient after

eyelids and third eyelid were held apart by self-retaining adjustable speculum.

3.1.9 Operative Procedures

3.1.9.1 Steps of Phacoemulsification: After the preliminary preparations including

placing of the speculum (Fig 11), one-handed phacoemulsification technique was

performed. The steps of phacoemulsification are described as follows:

a) Incision: A clear corneal incision through a 2.8 mm keratotome (Fig 12) at 6 o‟

clock position and a side port at the 2 o‟clock position using a slit knife/15˚ blade

was made to admit a lens dialer for use by the left hand (Kim et al 2008).

b) Staining of lens capsule and use of viscoelastics: Staining of the lens capsule was

done using trypan blue stain. The anterior chamber volume was restored with

viscoelastic material (hydroxypropyl methyl cellulose 2%).

c) Capsulorrhexis: A modified curved 24-gauged needle was used to cut into the

anterior lens capsule and form a window through which phacoemulsification

technique (Williams, 2004) was performed. The tear in the anterior capsule was

then extended with the help of a Utrata capsulorrhexis forceps (Fig 13) to perform

the continuous curvilinear capsulorrhexis according to that reported by Hill

(2005).

d) Hydrodisection: The lens was loosened from lens capsule by hydrodissection

using normal saline solution (Fig 14).

e) Phacofragmentation: The phacofragmentation tip was introduced through the

corneal incision and anterior capsulotomy to sculpt the central portion of the

cataractous lens, followed by nuclear rotation and phacoemulsification (Fig 15).

An initial deep trench was formed in the nucleus by the phaco tip. Using the dialer

36

in the left hand, the nucleus was rotated clockwise in the capsule to enable the

phacotip to make a second deep trench perpendicular to the first. Without utilizing

phacopower, the phacotip was placed in the inferior trench and pressed against the

left trench wall while simultaneously the dialer was pressed against the right

trench wall in order to crack the nucleus into two halves. The nucleus was then

rotated 90˚ counter clockwise to perform a second cracking. The first quadrant of

the nucleus was then phacoemulsified by engaging it on the phacotip and then

using pressure from the dialer on the anterior wall of the lens. After this the

remaining nuclear half was similarly cracked and the remaining three quadrants

phacoemulsified in the manner of the first (Fig 16).

f) Irrigation and Aspiration: Cortical clean up was done bimanually by placing the

irrigation and aspiration tip through the 6 o‟clock and 2 o‟clock ports. The

capsular bag was reinflated with visoelastic and final irrigation and aspiration was

done. The irrigation aspiration solution contained 500 ml balanced salt solution

and 1 ml adrenalin.

3.1.9.2 Implantation of artificial IOL: In group I A, rigid polymethylemethacrylate

(PMMA) lens was implanted in to capsular bag before enlarging the corneal incision.

The corneal incision was closed with 1 to 3 simple interrupted absorbable 6-0

ophthalmic Polyglactin 910 sutures as was deemed necessary (Kleiner 2011). In

group I B, square edge acrylic foldable lens was implanted. The IOL optic was folded

using IOL-holding forceps and inserted into the IOL cartridge (Fig 17). After filling

the capsular bag and anterior chamber with normal saline, the IOL in the cartridge

was inserted into the capsular bag with the IOL inserter without enlarging the corneal

incision (Fig 18). The corneal incision was closed by stromal hydration using normal

saline along the incision line which closed the incision (Fig 19).

3.1.9.3 Types of intraocular lens used

In Group I A, monofocal Poly methyl methacrylate (PMMA) lens was used

(n=5) and mono focal hydrophilic foldable acrylic IOL was implanted (n=22) of

group I B. The haptic design were either C or J shaped.

Fig. 11: Photograph showing fixing of Eye ball

Fig. 12: Photograph showing the clear corneal

incision using 2.8 mm Keratotome

Fig. 13: Photograph showing capsulorrhexis

using Utrata capsulorrhexis forceps

Fig. 14: Photograph showing hydrodisection using

normal saline to release any attachment between

lens capsule and lens cortex

Fig. 15: Photograph showing the introduction

of phaco tip through corneal incision to

sculpt and chop the cataractous lens

Fig. 16: Aphakic eye - post phacoemulsification

Fig. 17: Loading of foldable IOL in to the

IOL cartridge

Fig. 18: Implantation of IOL by IOL inserter

Fig. 19: Photograph showing the eye with

artificial IOL implanted

37

Lens Specifications Polymethylmethacrylate

Lens (PMMA)

3600Square Edge

Hydrophilic Foldable

acrylic Lens

Optic Design Equiconvex Equiconvex

Central Optic Diameter 5 mm 6 mm

Overall Length 12.50 mm 12 mm

A Constant 118.4 118.0

AC Depth 5 mm 5mm

Filtration UV UV

3.2 GROUP II (CORNEAL ULCERATION)

3.2.1 Diagnostic equipments: Different diagnostic equipments and eye solutions

were used for ophthalmic examination which included panoptic direct

ophthalmoscope, head mounted indirect binocular ophthalmoscope, 20 D lens for

indirect ophthalmoscopy, Tonopen-Vet tonometer, Fluorescein dye strips and

Schirmer‟s tear test strips.

3.2.2 Detailed Ophthalmic Examination.

Preoperatively, all the animals in group II underwent detailed ophthalmic

examination using following tests/criteria.

3.2.2.1 History - The history pertaining to the onset of ulcer, duration of vision loss,

details of earlier treatment (if any) of the animal were recorded.

3.2.2.2 Nature of Blindness - History pertaining to visual acuity during day and night

was obtained.

3.2.2.3 Tests of Blindness – Many tests were performed as per the standard

procedures to ascertain visual acuity. These included Menace Response (MR),

Pupillary Light Reflex (PLR), Palpebral reflex and Cotton Ball Test.

3.2.2.4 Special Diagnostic Procedures used by (Moore, 2003) were used as

following:

Special diagnostic tests carried out were ophthalmoscopy, Schirmer‟s Tear Test,

Fluorescein Dye Test (Fig 20) and Tonometry. These tests were carried out in same

38

manner as in group I.

3.2.3 Instrumentation

For surgical management of corneal ulceration equipments included self-

retaining eye speculum, mosquito forceps, straight and curved corneal scissors,

conjunctival scissors, iris scissors, Bard Parker handle No. 3, Bard Parker blade No.

11, Polyglactin 6/0 suture material, 24 G needle for performing grid and punctate

keratotomy (Fig 21) were used.

3.2.4 Pre-operative Procedures

Surgical preparation of the eyes included thorough lavage of conjunctival sacs

and cornea with povidone iodine solutions followed by flushing of the eye with sterile

saline. The eyelids were scrubbed with povidone iodine solution and washed with

sterile saline. Topical broad-spectrum antibiotics Gentamicin was administered 2

hours prior to surgery. Intravenous fluids were administered during surgery to ensure

adequate renal perfusion.

3.2.5 Anaesthesia

Same anaesthetic protocol was followed in group II as that of group I

3.2.6 Positioning and draping of the patient

Positioning and draping of the patients was done in same manner as in

group I

3.2.7 Operative Procedures

3.2.7.1 Corneal scarification

Corneal scarification was done by two methods, grid keratotomy (GK) (n=4)

and multiple punctate keratotomy (MPK) (n=4). Dogs treated with grid keratotomy

first had the loose epithelium debrided with sterile dry cotton swab. A linear or grid

keratotomy was then performed with a 24 gauge needle on a 2 ml syringe or by just

holding the needle hub (Fig 22). Small parallel linear incisions were made in a grid

like fashion through the epithelium and basement membrane to expose the underlying

corneal stroma. To do this, the needle was not allowed to penetrate no further than

0.2-0.3 mm deep and the linear incisions were placed 1-2 mm apart and extended

about 3mm into the normal epithelium surrounding the ulcer. Parallel lines were made

in a horizontal plane and then perpendicular to this in a vertical plane. Epithelial cell

Fig. 20: Photograph showing corneal ulcer

positive for Fluorescein dye test

Fig. 21: Ophthalmic surgical instruments

Fig. 22: Photograph showing grid keratotomy

39

migration occurs in these lines and enhances adherence to the corneal stroma. In

multiple punctate keratotomy small superficial punctures were made instead of

parallel lines (Fig 23). The eyes were closed by temporary tarsorrhaphy sutures. The

surgical outcome was accessed after seven days.

3.2.7.2 Conjuctival flap/ grafting technique

The recipient site was prepared to debride necrotic or infected corneal stroma

from the ulcer and surrounding cornea. The graft was derived from superior (Fig 24),

inferior or lateral bulbar conjunctiva whichever was closer to the lesion to allow the

graft traveling the shortest distance. The conjunctiva was elevated 1-2 mm posterior

to the limbus and incised. The tips of scissors were inserted; curve upward, through

the conjunctival incision and the bulbar conjunctiva was bluntly dissected from the

underlying capsule and episcelral tissues. The graft was then incised from limbus with

an incision parallel to limbus. The graft was then rotated on to the cornea using two

pairs of forceps and placed over the recipient site. The graft was sutured to the cornea

with simple interrupted stitches using 6-0 Polyglactin 910 absorbable suture material

(Fig 25). The eye was closed by third eye lid flap (Fig 26) and tarsorrhaphy (Fig 27)

was done. The animals were monitored for surgical out come for 15 days.

3.2.8 Post-operative care

In both the groups all dogs were required to wear Elizabethan collar at all

times during the first 2 weeks to prevent self-trauma. Excitements or any

compelling factors to dogs were limited to minimize postoperative complications.

Daily cleaning of the exterior of the operated eye with warm distilled water was

done for the first seven days. Post operatively cefotaxime @ 25 mg/kg and

Meloxicam 17 @ 0.2 mg/kg body weight were administered intramuscularly for 7 and

3 days respectively in both the groups. Gatifloxicin – Prednisolone18

drops were

instilled topically after every 2 hours for first week. This dose was tappered 4 hourly

for 2nd

week, four times a day for 3rd

week and two times a day for 4th

week. Atropine

drops were instilled three times a day for first three days to check the uveitis in group

17

Melonex: Intas Pharmaceutical Ltd.Ahmedabad Gujrat,India 18 Gatiquin – P: Cipla Pvt Ltd, Mumbai,India

40

I. In group II, Tobramycin 19

was instilled topically for 15 days. Carboxy methyl

cellulose sodium 20

lubricant drops were used for longer periods of time.

3.3 Blood Examination

Data related to complete blood examination and blood biochemistry (Serum

Creatinine, BUN, ALT, ALKP and Blood Glucose) was also recorded, whenever

feasible in both the groups.

3.4 Evaluation of surgical outcome

A successful surgical outcome was defined as restoration of functional vision,

assessed by response to a menacing gesture and the ability to navigate an obstacle

course. In group I, success rate was determined by dividing the number of eyes that

successfully restored the vision with the total number of the eyes operated for cataract

surgery and lens implantation. The incidences of intraoperative and post-operative

complications were also recorded. In group II, success rate was determined by noting

the healed cornea using different surgical techniques.

3.5 Statistical Analysis

In both the groups, Mean and Standard Error (S.E.) of various parameters

were calculated using Microsoft Excel.

19 Tobra: Taj Pharmaceuticals Pvt Ltd.Mumbai,India 20

Refresh Tears: Allergen India Pvt. Ltd, Pithampur, India

Fig. 23: Photograph showing the multiple punctate

keratotomy

Fig. 24: Procurement of graft from superior

bulbar conjunctiva

Fig. 25: Photograph showing conjunctival graft

on recipient site

Fig. 26: Photograph showing eye with third

eyelid flap

Fig. 27: Photograph showing eye with

tarsorrhraphy

CHAPTER IV

RESULTS AND DISCUSSION

Present study was conducted on a total of 48 cases of cataract (n=27) and

corneal ulceration (n=21) presented at Department of Veterinary Surgery and

Radiology, GADVASU, Ludhiana during the period from August 2013 to November

2015 for treatment. Study was conducted under two headings:

(A) CATARACT and (B) CORNEAL ULCERATION

4.1 CATARACT (GROUP I)

Animals were selected randomly for sub grouping after complete ophthalmic

examination. Results are presented collectively for subgroups till surgical procedure,

thereafter results are presented as per subgroups.

4.1.1 Signalment and history: Results of signalment and history shown by the

animals included in Group I of the study is presented below

A) Age wise distribution: During the observation period, the phacoemulsification

and implantation of intraocular lens was performed on 27 eyes of 23 dogs. Cataract

was seen in the age range of 6 months to 10 years with mean age of 9.72±0.41 years.

Age range of 6 to 10 years had highest incidence of 56.52% (n=13) followed by 6

month to 3 years 34.78% (n=8) and 3 to 6 years 8.61% (n=2). Ramani et al (2013) had

reported that the age group of 7 to 15 year had the highest incidence (50.22%) of

cataract followed by 3 to7 year age group (30.80%) and 0 to 3 year age group dogs

(19.5%) The higher incidence of cataract in the age range of 6 to 10 years in present

study might be due to the fact that dogs over 8 years usually have some degree of lens

opacity and metabolic alterations, such as those related to disorganization of lens

proteins, metabolic pumps, ionic concentrations and antioxidants (Sale et al 2013).

Table 2: Age wise distribution of canine cataract cases (Group I)

Group I

(n=27 of 23 dogs)

Age

6- 10 years 3-6 years 6 months – 3 years

56.52%

(n=13)

8.60%

(n=2)

34.78%

(n=8)

B) Sex wise distribution: Cataract was seen in majority of male dogs 86.95% (n=20)

and in fewer female 13.04% (n=3) which was also reported by Ramani et al 2013 and

42

Sale et al 2013. However, Nair and Vasanth (2007) observed a higher incidence

among the females (55.56%) than the males (44.44%).

Table 3: Sex wise distribution of canine cataract cases (Group I)

Group I

(n=27 of 23 dogs)

Sex

Male Female

86.95%

(n=20)

13.04%

(n=3)

C) Breed wise distribution: Breed wise distribution showed higher incidence of

cataract in German Shepherd (43.47%) followed by Labrador Retriever (21.73%),

Pomeranian (17.39%), Pug (8.69%) and Beagle and Dachshund (4.34% each).

Rajasekaran et al (2007) reported that Spitz was the most common breed with

incidence of (38.27%) followed by Non-descript (23.46%), Labrador Retriever

(11.11%), Lhasa Apso (7.41%), German Shepherd (6.17%), Boxer, Dachshund,

Cocker Spaniel, Doberman Pincher and Dalmatian 2.47% each. The higher incidence

of cataract in German Shepherd in present study may be due to the popularity of the

breed in this region.

Table 4: Breedwise distribution of canine cataract cases (Group I)

Breed No of animals (%)

Group I (n=27 of 23 dogs)

German Shepherd 10 (43.47%)

Labrador Retriever 5 (21.73%)

Pomarenian 4 (17.39%)

Pug 2 (8.69%)

Dachshund 1(4.34%)

Beagle 1 (4.34%)

D) Classification of cataract: In the present study, cataracts were classified as Senile

81.48% (n=22) followed by Diabetic 14.81% (n=4) and Juvenile 3.70% (n=1).

Diabetes mellitus induces cataract of usually acute bilateral occurrence (Wilkie et al

Fig. 28: Age wise distribution of canine cataract cases of Group-I

Fig. 29: Sex wise distribution of canine cataract cases of Group-I

Fig. 30: Breed wise distribution of canine cataract cases of Group-I

56.52%

8.60%

34.78%

6 - 10 Years3 - 6 Years6 M - 3 years

86.95%

13.04%

Male

Female

43.47%

21.73%

17.39%

8.69% 4.34% 4.34%

German Shepherd

Labrador

Pomarenian

Pug

Dachshund

Beagle

43

Table 5: Classification of canine cataract cases (Group I)

Group I

(n=27 of 23 dogs)

Classification of Cataract

Senile Diabetic Juvenile

81.48%

(n=22)

14.81%

(n=4)

3.70%

(n=1)

2006). It often rapidly progresses and blindness can develop within a period of weeks

or even days (Gould 2002). Gwin and Gelatt (1985) suggested that senile cataract

generally occurred in dogs over six years of age. The increase in incidence of cataract

with senility might be due to gradual degeneration of lens fibers as a result of ageing

of the lens components (Williams 2004).

E Stage of cataract according to maturity: In the present study, mature cataract was

found in the 92.59% (n=25) cases and immature cataract was found only in 7.40%

(n=2) of eyes examined in group I. Martin (2010) found mature cataracts being the

most common followed by immature, hypermature and insipient, but differed as the

percentage of the population found to suffer from mature cataracts was substantially

lower (73.2%) when compared with the results of the present study. The mature

cataracts in the present study might be due to late presentation of the cases by owners.

Table 6: Stage of canine cataract cases (Group I)

Group I

(n=27 of 23 dogs)

Stage of Cataract

Mature Immature

92.59%

(n=25)

7.40%

(n=2)

F) Occurrence of the cataract: Occurrence of cataract in group I was bilateral in

96.29% (n=26) and unilateral 3.70% (n=1) cases. Jhala et al (2009) and Mistry (2010)

also observed bilateral cataract in various developmental stages in their respective

studies. Although bilateral cataract occurs in dogs due to various etiological factors, in

our study, it might be due to senility as the incidence was high amongst dogs with

mean age of 9.71±41years.

44

Table 7: Occurrence of canine cataract cases (Group I)

4.1.2 Selection of cases for study: Clinical cases for this study were selected after

evaluation of the stage of cataract and degree of vision loss using various methods

already described. All dogs underwent physical examination, complete blood counts

and serum biochemistry to determine if they were suffering from any systemic

diseases.

4.1.2.1 Haematobiochemical Parameters: Heamatobiochemical parameters in all

the dogs were well within the range except for blood glucose in four dogs which had

elevated blood glucose levels (188mg/dl, 426mg/dl, 225 mg/dl and 339mg/dl) which

were put on Insulin. These results are in accordance with Jhala et al (2009). Routine

haematobiochemical estimation is very important to rule out any systemic and

endocrine abnormality in cataractous dogs (Jhala et al 2009, Ahmad et al 2005).

Table 8: Haematobiochemical (Mean±SE) parameters of canine cataract cases

(Group I)

Parameter Units Mean±SE

Haemoglobin g/dl 13±1.2

TLC (103 x/µl) 14500±3.5

DLC Neutrophil % 77.8±1.9

Lymphocyte % 21.3±1.5

SGPT/ALT IU/l 34±6.2

ALKP IU/l 31±8.5

BUN mg/dl 16±3.3

Creatinine mg/dl 0.8±0.06

Blood glucose mg/dl 95±27

Group I

(n=27 of 23 dogs)

Occurrence of Cataract

Bilateral Unilateral

96.29%

(n=26)

3.70%

(n=1)

Fig. 31: Classification of canine cataract cases of Group-I

Fig. 32: Stage of canine cataract cases of Group-I

Fig. 33: Occurrence of cataract cases of Group-I

81.48%

14.81%

3.70%

Senile

Diabetic

Juvenile

92.59%

7.40%

Mature

Immature

96.29%

3.70%

Bilateral

Unilateral

45

4.1.3 Ocular biometric analysis

4.1.3.1 A - Scan: The A-mode ultrasonography of the eye required the direct contact

between the transducer probe and the cornea hence topical anaesthesia (0.5%

proparacaine) proved useful in all cases. The dogs needed to be positioned in sternal

recumbency during the ultrasonographic procedure (Martins et al 2011). The

transducer needed to be placed in direct contact with the center of the cornea for

obtaining ocular measurements by averaging six consecutive measurements (Mobricci

et al 2009, Rubin et al 1969).

The mean axial length and anterior chamber depth pre operatively for group I

was 21.20 ± 0.38 mm and anterior chamber depth (ACD) was 4.10 ± 0.30 mm. The

mean axial length was found to fall within the range of 19.5 to 21.9 mm as reported

by Cook (2008). Martins et al (2011) was also of a similar opinion and reported a

range of 17.10 to 21.01mm. Williams (2004) reported smaller ACD's of 3.5 ± 0.1 mm

in eyes with immature cataract and 3.2 ± 0.6 mm in eyes with mature cataract.

The mean lens thickness was 5.89 ± 0.33 mm and ranged from 3.42 mm to

7.66 mm. Lens thickness measured by Martins et al (2011) ranged from 5.84 to 10.83

mm (mean ± SD: 7.87 ± 1.5 mm) and was not different from the values in this study.

4.1.3.2 Central corneal thickness (CCT): Knowledge of the dimensions of the

optical components is required for better understanding of many research and clinical

problems in vision (Wong and Foster 2001). The mean central corneal thickness in

present study was 0.60±0.03 mm in group I. Ultrasonic Pachymetry is the most

accurate available clinical technique to measure corneal thickness (Gonzalez et al

2015, Gilger et al 1991). Measurements of normal canine corneal thickness have

ranged from 0.61 – 0.95 mm (Prince et al 1960). The central corneal thickness in

young dogs ranged from 0.4 to 0.6 mm, in adult dogs from 0.49 to 0.6 mm and in old

dogs CCT range was 0.49 to 0.73mm (Gilger et al 1991). In four of the diabetic dogs

the mean central corneal thickness was comparatively more than other non diabetic

dogs. Diabetic keratopathy is a frequent disease that entails several alterations,

especially in the epithelium and endothelium. Corneal epitheliopathy appears as

46

Table 9: Preoperative calculation of different ocular biometric parameters in canine cataract cases (Group I)

A - mode ultrasonography parameters Central corneal

thickness

(CCT)(mm)

Schirmer’s tear

test

(STT)(mm/min)

IOP mmHg

Anterior Chamber

Depth

(ACD)(mm)

Lens thickness

(LT) (mm)

Axial length

(AXL) (mm)

Group I

(n=27 of 23 dogs)

4.10± 0.30

5.89±0.33

21.20±0.38

0.60±0.03

20.0±2.56

16.25± 3.34

Ref. Range

3.2-5.19*

5.85- 10.83*

17.10 – 21.01*

0.6-0.72**

15-25mm/min**

10-20mmHg**

*Cook (2008), ** Gellat (1991)

47

punctate keratitis, decreased adherence to the basal membrane and corneal

hyposthesia. Alterations on the endothelium result in a deficient pumping function, as

well as cell alterations, and possibly endothelial thickening and folds (Donnell et al

2001, Wilkie et al 2006).

4.1.3.3 Tonometry and Schirmer’s tear test: Pre-operatively the IOP was checked

to detect the presence of early stages of glaucoma and the presence of lens induced

uveitis (Hlinomazová and Vlková, 2003).

The mean Intraocular pressure (IOP) in Group I was 16.25± 3.34 mmHg.

Gelatt (2007) reported low IOP suggested lens induced uveitis (LIU), while the

presence of a high normal to elevated IOP suggests early primary or secondary

glaucoma. The intraocular pressure was checked prior to operation to detect early

rises in IOP as opined by Klein et al (2011) who performed the test at 2 hours before

surgery.

The Schirmer‟s tear test value in group I was 20.0±2.56 mm wetting/ min, the

readings were well within the normal range in all the dogs undergoing cataract

surgery. Normal values of Schirmer‟s tear test were also observed by Mistry (2010) in

canine cataract cases undergoing phacoemulsification.

4.1.4 Visual function tests

4.1.4.1 Menace test: A menace response was not elicited by any of the dogs pre-

operatively, due to the presence of mature cataract lenses preventing the visualization

of the threatening gesture toward the respective eye and conversely also preventing

the examiner a view of the ocular fundus (Gaiddon et al 1988, Martin 2010). The

palpebral reflex was initiated in all eyes after testing for the presence of a menace

reflex to confirm the functioning of the motor cortex, facial nucleus and subsequent

structures involved in the efferent pathway (Gelatt, 2007).

4.1.4.2 Pupillary light response: Ophthalmic examination showed complete vision

loss in 24 eyes with mature cataract, while the 2 eyes with immature cataract had

moderate vision, and one dog with unilateral cataract had intact vision. The pupillary

light reflex was seen in all eyes that underwent surgery pre-operatively. PLR

indirectly assess retinal function and the integrity of the sensory and motor functions

of the eye (Tuntivanich and Tuntivanich, 2007). Startup (1967) considered pupillary

48

response to the light an essential evaluation factor during cataractous eye

examination. Absence or weak reflex could be considered positive for degenerative

retinal changes. In the current study, dogs positive for pupillary light reflex regained

their vision after surgery, thus this reflex is a reliable indicator of intact retinal and

sensory and optic nerve functions.

4.14.3 Obstacle course test: The use of the obstacle course test to evaluate vision

after phacoemulsification and lens implantation surgery was designed by Ozgencil

(2005). Except two dogs (one with unilateral and one with immature cataract), none

of the dogs were able to negotiate the obstacle course under well lite conditions.

Gelatt (2007) stated that it was the ability of the animal to navigate in an unfamiliar

environment. The dog was made to wait at the end of the examination room,

throughout which 10 random objects of different sizes were placed. The owner was

made to gesture at the dog. The dog was assessed for its ability to move through the

room without touching any of the obstacles, the speed and the amount of reluctance of

the dog while moving through the room, the position of the dogs head and posture

relative to the ground and the ability of the dog to stop without bumping into the door

at the end of the obstacle course. Gelatt (2007) also opined keeping the design of the

course consistent so that the various patients could be equally evaluated.

The cause of the pre-operative inability to navigate through the course was

attributed to the mature stage of the cataract (Honsho et al 2007).

4.1.5 Surgical management of cataract patients: All the dogs that received topical

antibiotic Gentamicin, 1% Tropicamide and Atropine eye drops as mydriatic agents

and 0.5% Povidone Iodine for ocular antisepsis 2-3 times prior to surgery showed

reduced intraocular infection and also helped in dilatation of pupil before and after

surgery. Adkins and Hendrix (2003) suggested the need for pre operative treatment

before cataract surgery to decrease the amount of intra operative and post operative

intraocular inflammation, decrease the conjunctival bacterial flora, dilate the pupil,

and prevent miosis during surgery. Application of topical antibiotic is usually initiated

24 hours before surgery. These drugs prevent intraoperative infection by decreasing

bacterial load of the eye. Brookshire et al (2013) stressed highly on use of topical

antibiotics for controlling intraocular infection and capsular opacification after

49

phacoemulsification. Topical atropine used at the time of induction of anaesthesia is

advantageous in preventing miosis (Yi et al 2006). Williams et al (1996) reported that

for cataract surgery pupillary dilatation is mandatory. It was observed that 0.5%

tropicamide and 10% phenylephrine produced satisfactory mydriasis (Kovalcuka et al

2013). Coaxial binaocular operating microscope provided satisfactory visualization of

the operative field. A good operating microscope system is extremely important.

Visibility is essential for successful grasping and manipulation of the capsule and

capsulorrhexis is usually easier under higher magnification (Ruth 2003).

In human medicine most uncomplicated cases are operated in local

anaesthesia (Fichman 1996), and the complicated cases in general anaesthesia –

systemic neuromuscular blocking agents (Davis and Mandel 1994). In veterinary

medicine general anaesthesia is evidently imperative. Most veterinary surgeons prefer

systemic neuromuscular blocking agents, because it markedly simplifies the

procedure by eliminating bulbar rotation (Nasisse and Davidson 1991). Intravenous

injection of ketamine hydrochloride @ 5mg/kg body weight and diazepam @

0.5mg/kg body weight mixture was used for maintaining anaesthesia which provided

optimum depth of anaesthesia (Kleiner, 2011).

Peribulbar nerve block using 2% lignocaine resulted in protrusion of eyeball

which is mandatory for intraocular surgery (Mistry, 2010, Joy et al 2011). Otherwise

it would have been difficult to access the eyeball in anaesthetized dogs as it sinks

inside the orbital cavity, due to the contraction of orbicularis oculi muscle. Kleiner

(2011) in his study administered sodium chloride 0.9% into the retrobulbar space

using a 22 gauge needle, entering behind the lateral aspect of the zygomatic arch in

order to push the globe forward for exposure. In the present study, self restraining eye

speculum and a stay suture using Polyglactin 910 suture material held by other

assistant during surgery resulted in better exposure of eye ball. In contrast, Kleiner

(2011) observed that there was greater advantage of not having the blepharostat

holding the eyes open as it added no pressure in the globe and there was less leakage

from the incision and the anterior chamber was well maintained. (Williams et al 1996,

Jhala et el 2009) recommended lateral canthotomy to enlarge the palpebral fissure

which improves the exposure of the operative site.

50

Group I A (Phacoemulsification and implantation of rigid PMMA lens): In group

I A (n=5) phacoemulsification helped in satisfactory cataract extract extraction and

there by for implantation of rigid intraocular lens polymethylmethacrylate (PMMA)

of +41D. The effective treatment for cataract management is the surgical extraction of

cataractous lens (Ameerjan 2005). Phacoemulsification is an ideal procedure for

cataract extraction in both human and veterinary practices (Sigle and Nasisse, 2006,

Ramani et al 2011, Goes et al 2013). The incision was enlarged up to 1 cm to

accommodate the rigid polymethylmethacrylate (PMMA) lens. Although

phacoemulsification requires a 2.7 – 3.5 mm incision, but in case of PMMA lens the

wound must be large enough to accommodate it (Kim et al 2008). The dogs were left

with pseudophakic vision with artificial IOL implanted. Ofri (2008) suggested that

dogs will be able to see better post-operatively with artificial IOL implanted as lens

provides an increased refractive power to the eye. Therefore, successful removal of

the cataract IOL implantation will enable the patient to regain vision. Tight wound

closure causes post operative astigmatism which got resolved within due course of

time (Davidson et al 1990).

Group I B (Phacoemulsification and implantation of foldable lens): In group I B

(n=22) square edge acrylic foldable lens of +41D was implanted after

phacoemulsification. In the present study, 2.8 mm keratotome satisfactorily helped in

clear corneal incision on 6 o‟clock position and a side port at the 2 o‟clock position

using a slit knife/15˚ blade was helpful to admit a lens dialer for use by the left hand.

There are three possibilities for access to the lens: clear corneal, limbal or scleral-

based approach (Nelms et al 1994). No bleeding was observed in the present study

using clear corneal incision. Similar results were observed by Jhala et al (2009) using

Brad Parker blade No 11 at 10 o‟clock to 2 o‟ clock position which resulted in less

intraoperative bleeding and better postoperative wound healing. Nasisse et al (1991)

observed that the use of limbal incision has an increased incidence of complications.

In dogs the lens is most easily accessed by clear corneal incision, which is also the

easiest to create; on the other hand it leads to greater degree of astigmatism and

fibrosis and it is more critical to precisely appose wound edges to achieve water

tightness (Nelms et al 1994). In this study side port at 2 o‟ clock position was

satisfactorily admitting the trypan blue dye for staining of lens capsule.

51

Trypan blue is a vital stain classically used to stain the anterior lens capsule,

presenting no toxicity in concentrations as high as 0.3%. Since it does not poses any

risk of lowering intra operative visibility. While performing the surgery it has been

noted that trypan blue staining of the anterior capsule appears to be a safe technique to

facilitate the performance of a capsulorhexis in the absence of a red fundus reflex

(Melles et al 1999). The safety of intra operative use of trypan blue in extracapsular

cataract surgery has already been proved with follow-up periods up to 8 years

(Karthigeyan 2013).

Viscoelastic material used in the present surgery facilitated iris dilation and

manipulation of the phaco tip in to the capsular bag with minimal iris damage.

Hydroxypropyl methylcellulose (viscoelastic material) was injected intra-ocularly

from the main port to maintain the stability and integrity of the anterior chamber, coat

and to protect the intraocular tissues and to control haemorrhage (Glover and

Constantinescu 1997). Whitley (1999) recommended the use of viscoelastic material

to protect the corneal endothelium during the intraocular surgery.

In present study, capsulorhexis was performed using 26 guage double bended

hypodermic needle after that continuous 360 curvilinear capsulorhexis was performed

using Utrata capsulorhexis forceps. Similar technique was adopted by (Jhala et al

2009) in their study. Bernays and Peiffer (2000) indicated that thickness of the

anterior lens capsule in dog increases with age.

In present study, one handed phacoemulsification technique was satisfactorily

used for extraction of immature cataractous lens and bimanual technique for hard

mature lens with lens dialler enabling the manipulation of hard cataractous lens far

from posterior capsule and also helping in pushing the hard lens fragments towards

and in to the phaco tip. Hydrodissection enables division of the lens material from the

capsule using application of normal saline solution between the capsule and the lens

through 27G cannula (Gimbel 1991). In some cases it can be useful to perform

hydrodissection after sculpting the nucleus (Nasisse and Davidson 1991). In some

bimanual techniques, especially in cases of hard nuclei, hydrodelineation is also used

(Yi et al 2006). The principle of phaco is to sculpt and fragment the nucleus and

subsequently remove it by aspiration and aspirate all remaining cortical material

52

(Kelman 1994; Nasisse and Davidson 1991). One-handed technique has the advantage

in the possibility of using the non-dominant hand for manipulation with the globe and

it is easier to learn (Obstbaum 1987). With bimanual technique the surgeon uses his

second hand to manipulate the nucleus with special intraocular instrument through the

side port (Gaiddon et al 1988). In this study, bimanual irrigation and aspiration

technique was used with different ports. After emulsification of the nucleus, it is

necessary to remove all remaining cortical material to avoid post-surgical

complications (Nasisse and Davidson 1991). One can use either one-handed or

bimanual irrigation and aspiration (I/A), the latter being the method of choice for most

surgeons (Gilger et al 1993).

Artificial Intraocular lenes serve as optimal correction of aphakia (Ridley

1952). In present study, hydrophilic acrylic square edge foldable + 41D lens was

implanted. The optic power most commonly used is 41D (Gaiddon et al 1991), the

sizes differ from 14 to 18 mm (haptic size), with 7 mm optic. Although there have

been many discussions whether to implant IOLs in dogs or not (Bigelbach 1994), at

present time most surgeons tend to implant IOL in dogs (Nasisse et al 1990; Davidson

et al 1991; Gaiddon et al 1991; Nelms et al 1994). There are two main types of IOLs

used in veterinary medicine – hard PMMA and foldables and acrylic polymers

(Gilger et al 1993, Gaiddon et al 1997). Most implanted lenses in dogs are PMMA,

although recently many surgeons tends to use soft, foldable lenses. Gaiddon et al

(1997) described use of silicon lens. The latest type of soft lenses designed for dogs

are made of hydrophilic acrylate. The unquestionable advantage of acrylic lenses is

the size of incision as well as the excellent biocompatibility (Nelms et al 1994).

The frequent problems during the placement of IOL is miosis however in this

study flexible IOL was inserted in to the capsular bag through an IOL cartridge

opening which corresponds to the corneal incision length of 2.8mm (Yi et al 2006).

Acrylic square edge IOL lens is associated with lower incidence of post operative

complications. This is because acrylic lenses have strong adhesions to the posterior

capsule and specific optical design can inhibit the migration of the lens epithelial cells

in to the optic area (Davidson 2001). Stromal hydration of the clear corneal incision

53

was conducted to facilitate self sealing by placing the tip of a 27 gauge cannula on the

side walls of the incision (Kim 2008).

4.1.6 Success rate: With dramatic development of phacoemulsification in the past

decade this technique allows surgeons to increase wound stability, reduce ocular

trauma and hopefully eliminate post operative astigmatism and prompt more rapid

recovery of optimal vision (Koch 1991). The principle advantage of two-handed

phacoemulsification technique used in this study was a greater flexibility in lens

manipulation afforded by having two instruments in the eye. Theoretically the two-

handed technique results in quicker and safer surgery because the lens can be cracked

without the need for sculpting near the posterior capsule, and the lens can be fed to

the phaco tip. This technique also allows for a larger diameter capsulorhexis, because

the second instrument can keep large fragments of lens material out of the anterior

chamber (Glover and Constantinescu, 1997).

In present study 1 out of 5 eyes in group I A (n=5) and 15 out of 22 in group I

B (n=22) had successful recovery after phacoemulsification with implantation of

rigid PMMA of +41D and foldable acrylic of +41D lens respectively. The success of

surgery was based on post operative restoration of vision as evaluated by various

tests. Total success rate was 20% in Group I A (n=5) and 68% in Group I B (n=22).

Similar success rate was reported by Jhala et al (2009). However, Brikshavana

(2007), Mistry (2010) and Klein et al (2011) reported 96%, 100% and 82.7% of

success rate respectively. The lower success rate in this study might be due to

adoption of technique, postoperative treatment regimens, and intensive care of owners

(Davidson et al 1991). Before the common use of phacoemulsification for cataract

removal in dogs, the ideal stage for removal was a mature cataract. With current

surgical techniques and ocular medications, however, the prognosis for long-term

vision is quite good with earlier removal of cataractous lens, and the immature stage

is now considered ideal (Adkins and Hendrix, 2003). For visual outcome, several

examinations were performed pre- and post-surgery. The surgery is considered

success if vision is restored post-operatively and maintained at the last evaluation. In

order to determine regained vision, dogs were required to have positive menace

response in addition to pass maze test at times of evaluation (Chahory et al 2003).

54

4.1.6 COMPLICATIONS

Phacoemulsification has been performed in veterinary medicine for decades

and is used to restore sight to animals blinded by cataract (Miller et al 1987).

Although there have been significant advances in cataract surgery, complications

persist (Bai et al 2015). These complication may occur pre operatively, intra

operatively or post operatively (Johnsen et al 2006). These complications can be

transient and medically treated, or can be more serious resulting in blindness and pain

(Gellat and Mackay 2004). In present study, surgical complications were categorized

into 2 phases: intra-operative and post- operative.

4.1.6.1: Intra-operative complications: Several intra-operative complications

occurred in both the groups at different time points during the surgery. Pupil

constriction (miosis) occurred in 4 dogs immediately after cornea was incised and for

the second time after the lens had been partly sculpted (Tuntivanich and Tuntivanich,

2007). Blood in anterior chamber (hyphema) (Fig 34) was observed in three of the

four dogs of which pupil had become constricted during phacoemulsification

procedure in Group I A (n=5) in which rigid IOL was implanted. Iris buldging

occurred in one dog in this group. In group I B (n=22), miosis occurred in only 2

dogs. Mistry (2010) also encountered such intra operative complications and iris

sphincterotomy was performed in one such case. Honsho et al (2007) also reported

that more intraoperative complications for the eyes submitted to extracapsular cataract

extraction than phacoemulsification.

In the present study to prevent miosis during surgery, adrenaline or heparin

sodium added into the irrigation solution helped in dilatation of pupil. Adrenaline is

recommended to instill into the anterior chamber to quickly dilate the pupil (Petersen

and Clutton 1994). Heparin not only can reduce fibrinoid reaction, it can also prevent

intra-operative pupil irregularity and post-operative inflammation (Bayramlar et al

2004). PMMA IOL requires a larger corneal incision and more surgical trauma which

may be the reason that miosis and intraocular haemorrhage was more likely in eyes

with PMMA IOL placement.

4.1.6.2: Post operative complications: In this study the most common post operative

complication seen was corneal opacity and uveitis in both the groups but the severe

Fig. 34: Photograph showing intraoperative

hyphema

Fig. 35: Photograph showing the slight Corneal

Opacity after phacoemulsification

Fig. 36: Photograph showing clear Cornea

15 days after phacoemulsification

55

post operative complications were observed in group I A. In group I B slight corneal

opacity (Fig 35) and uveitis was seen in two dogs. Dogs developing slight corneal

opacity got resolved within 15 days (Fig 36) of time and restoration of vision was

seen, however, 80% of dogs in group I A and 32% in group I B did not regain vision

due to severe corneal opacity. The potential post operative complications of canine

phacoemulsification surgery are numerous and include corneal edema, corneal

ulceration, corneal opacity, uveitis, glaucoma, posterior capsule opacification and lens

fiber regrowth, posterior capsular tears, vitreous loss, lens drop, retinal detachment,

endophthalmitis, and wound dehiscence (Brikshavana 2007). Jhala et al (2009) also

reported development of corneal opacity in eyes undergone extracapsular cataract

extraction, however, the corneal opacity resolved within 3 weeks of time. The non

restoration of the vision in group I A (n=5) in present study may be attributed to large

corneal incision for accommodation of rigid lens and more trauma caused to the eyes

which could have damaged the corneal endothelium and resulted in severe corneal

opacity and corneal oedema. In group I B there was restoration of vision in 68% eyes

suggestive of the fact that implantation of the square edge acrylic foldable lens was

easy to implant and caused less trauma. Uveitis was another post operative

complication in both the sub groups. Tuntivanich and Tuntivanich (2007) observed

that phacolytic uveitis is the most common complication that occurs following

phacoemulsification surgery followed by posterior capsular opacification. However,

in the present study, there was no incidence of posterior capsular opacification (PCO).

In this study, gentamicin was therefore selected for pre-operative treatment while

gatifloxacin – prednisolone was selected postoperatively helped in controlling

inflammation and infection satisfactorily. Topical and systemic treatment by

antibiotics steroidal anti-inflammatory drugs can control uveitis pre- and post-

operatively. Ketorolac tromethamine showed low efficacy reducing inflammation but

less likely to induce ocular hypertension after phacofragmentation and aspiration

surgery compared to fluorometholone acetate (Trinavarat et al 2003).

56

4.2 CORNEAL ULCERATION (GROUP II)

Similar to group I, as in group II also the animals were selected randomly for

sub grouping and results are presented collectively for sub groups till the surgical

procedure. Thereafter, the results are presented as per sub grouping

4.2.1 Signalment and History: Results of signalment and history in Group II are

presented below:

A) Age wise distribution: During the observation period corneal ulceration was

found in the age range of 2 months to 8 years with mean age of 2.4±1.71years.

Highest incidence of corneal ulceration was seen in the age range of 2 months to 1

year 61.90% (n=13) followed by in age range of 2 to 4 years 23.80% (n=5) and 5 to 8

years 14.28% (n=3). These finding are in accordance with Ramani et al (2012).

Moore (2003), had reported the corneal ulcer incidence was high in middle aged dogs

with a mean age of 8.2 years. Wilkie and Whittaker (1997) reported that older dogs

appeared predisposed and yet dogs of any age could be affected. Therefore, it can be

inferred from present study that incidence of corneal ulceration is remarkably high in

young dogs due to their most active life period where corneal traumatic injury is most

prevalent.

Table 10: Age wise distribution of corneal ulceration cases (Group II)

Group II

(n=21)

Age

2Months – 1 Year 2-4 Years 5-8Years

61.90%

(n=13)

23.80%

(n=5)

14.28%

(n=3)

B) Breed wise distribution: Breed wise distribution of corneal ulceration showed

corneal ulceration mostly in Pugs 95.23% (n=20) and German Shepherd 4.76%

(n=1). Ramani et al (2012) also reported highest incidence of corneal ulceration in

Pug. Whereas Jose (2004) found incidence of corneal ulcer in spitz (51.85%), Non-

Descript (22.22%), Lhasa apso (7.41%),Great Dane, German shepherd, Pug, Bull

terrier and terrier (3.7%). Moore (2003) reported that corneal ulceration was observed

in over 45 different breeds of dogs with Boxer being the most common breed with

(24.56%) incidence, followed by mixed breed (11.03%), but a high number of cases

occurred in Poodles, Golden retrievers, Corgie, Labradors Springer spaniel and GSD.

57

Brachycepahlic dogs lack many of the protective meachanisms operant in

mesocephlic amd dolicocepahlic breeds (Barrett et al 1991). The pronounced globe

position of brachycepahalic dogs predispose the eye to ocular trauma and

exophthalmia prevents normal palpebral apposition and leads to lagophthalmos

(Carrington et al 1989). Brachycepahlic dogs often have a thin lipid layer in the tear

film and decreased aqueous coverage in the central cornea as a result of of less

blinking reflexes (Moore 2003). Moreover corneal sensitivity in brachycepahlic is

lower, compared with sensitivity of mesocepahlic and dolicocephalic dogs (Barrett et

al 1991). The inherent lower corneal sensitivity and protrusion of the globe in

brachycepahlic dogs negatively affect function of cornea‟s protective mechanisms,

leads to an increased opportunity for traumatic injury and allow ulcers in the early

stages to go unnoticed by owners (Hakanson and Merideth 1987).

Table 11: Breed wise wise distribution of corneal ulceration cases (Group II)

Group II

(n=21)

Breed

Pug German Shepherd

95.23%

(n=20)

4.76%

(n=1)

C) Sex wise distribution: In the present study a high incidence of corneal ulceration

was found in males 76.19% (n=16) than in female 23.80% (n=5) dogs. Results of

present study are in accordance with those reported by Ramani et al (2012) and

Moore (2003). However, Wilkie and Whittakar (1997) reported that dogs of any sex

could be affected by corneal ulcer.

Table 12: Sex wise distribution of corneal ulceration cases (Group II)

Group II

(n=21)

Sex

Male Female

76.19%

(n=16)

23.80%

(n=5)

D) Causative factor: There are many causes of corneal ulceration failing to heal

(Stanley et al 1998). In present study, commonest cause of corneal ulceration was

lagophthalmos (80.95%) followed by trauma (19.04%). This study is in accordance

with earlier studies of (Gellat 1991), Moore (2003). However, Kim et al (2009)

58

reported Keratoconjunctivitis sicca (KCS) as the commonest cause of ulcerative

keratitis (31%) followed by lagophthalmos (28%), bacterial infection (11%), nasal

fold trichiasis (11%), and trauma (8%). Etiologies may be congenital or result from

infection, allergy, trichiasis, distichiasis, ectopic cilia, entropion, trauma, foreign

body, or lack of tears (Crispin 2002, Martin 2005, Gilger et al 2007). In some cases a

predisposing cause can be found and once corrected the corneal ulcer usually heals

rapidly. With some cases no cause can be identified and these are called as persistent

corneal erosions (Kirschner 1990).

Table 13: Causative factor of corneal ulceration cases (Group II)

Group II

(n=21)

Causative factor

Lagophthalmos Trauma

80.95%

(n=17)

19.04%

(n=4)

E) Symptoms: In present study conjunctival hyperemia (Fig 42) was present in all

affected eyes along with varying degree of corneal opacity (Fig 43) and it was mostly

corneal edema and/or neovascularization of the epithelial tissue in affected eyes.

Signs of pain and irritation were also observed in affected eyes. Animals with corneal

ulcers present clinical signs of epiphora, pawing, blepharospasm, photophobia, and

corneal opacity (Gilger et al 2007). The signs of pain associated with keratitis or

corneal ulcers may arise from direct stimulation of sensory corneal nerves and ciliary

muscle spasm secondary to reflex anterior uveitis which were also observed by Kern

(1990). Kern (1990) stated that neovascularization denotes complicated ulceration, in

which healing was delayed by ocular (eyelid defects, infection) or non-ocular factors

(self-trauma, inappropriate medical therapy). Magrane (1969) stated that vessels

invade cornea in response to various pathologic processes in vascularized method of

corneal stromal healing.

F) Location of the Ulcer: In the present study, 57.14 % of the ulcers were central,

23.80% (Fig 44) were dorsonasal and 19.04% were ventronasal (Fig 45). Similar

findings were also reported by Dorbandt et al (2015). The higher percentage of

centrally located corneal ulcers might be due to exophthalmia which prevents normal

Fig. 37: Age wise distribution of corneal ulceration cases of Group-II

Fig. 38: Breed wise distribution of corneal ulceration cases of Group-II

Fig. 39: Sex wise distribution of corneal ulceration cases of Group-II

61.90%

23.80%

14.28%

2 M - 1 year

2-4 Years

5-8 Years

95.23%

4.76%

Pug

German Shephered

76.19%

23.80%

Male

Female

56

57

Fig. 40: Causative factor of corneal ulceration cases of Group-II

Fig. 41: Location of corneal ulceration cases of Group-II

80.95%

19.04%

Lagopthalmos

Trauma

57.14% 23.80%

19.04%

Central

Dorsonasal

Ventronasal

58

Fig. 42: Photograph showing conjunctival

hyperaemia in a dog with corneal ulcer

Fig. 43: Photograph showing corneal opacity

in a dog with corneal ulcer

Fig. 44: Photograph showing central Corneal

ulcer in a dog

59

palpebral apposition and leads to lagophthalmos and ultimately leads to uneven

distribution of the tear film at central region of the cornea.

Table 14: Location of corneal ulceration cases of Group II

Group II

(n=21)

Location of the ulcer

Central Dorsonasal Ventronasal

57.14%

(n=12)

23.80%

(n=5)

19.04 %

(n=4)

4.2.2 Ophthalmic diagnostic tests: Due to its anatomical structure, the eye permits

direct observation of many pathologic processes as they develop (Gellat 1991). The

vast majority of ophthalmic conditions can be diagnosed with a few relatively simple

tools and techniques that almost every veterinarian can learn and use in clinical

practice (Hollingworth et al 1992). Ophthalmic diagnostic tests carried out in the

present study were Schirmer‟s tear test, IOP measurement and Fluorescein dye test in

all animals of groupII. In group II, the mean STT reading was 07.4± 1.33 mm

wetting/min. The values observed in present study are lower than the normal range of

canine tear production (15-25 mm wetting/min). The lower value of STT may indicate

predisposition towards KCS which may be the inciting cause of corneal ulceration.

The findings of this study are in accordance with Kim et al (2009).

The mean IOP of affected eyes was within the normal range except in two

eyes (30 mmHg and 33 mmHg) which were treated with Acetazolamide @ 3mg/kg

body weight and topical Timolol eye drops. The values reduced to average values

after 15 days of treatment. Gellat et al (1982) used carbonic acid inhibitors for short

and long term management of canine glaucoma with twice daily administration.

Townsend (2007) pointed out that topical beta blockers administered 8-12 hours

interval decreased production of aqueous humor and there by IOP also. Hasegawa et

al (2001) opined that lower IOP can be maintained with medical treatment alone in

dogs for a long period with open angle glaucoma.

Fluorescein stain aids in the diagnosis of corneal ulceration, the dye not only

stains the ulcerated area, but also migrates under the loose flaps of the epithelium and

stains the surrounding anterior stroma, and this makes the ulcer appear larger than the

actual size (Whitley and Gigler, 1999, Moore 2003). All unhealthy corneas stained

greenish with fluorescein dye using commercially available fluorescein strips. The

60

test was positive in 20 out of 21 (95.2%) affected eyes. In one eye, only the margins

took the stain because the ulcer was so deep that the corneal stroma had abraded

resulting in protrusion of descemets membrane commonly this condition is called as

descematocele. Only the ends of abrasive cornea stained greenish in cases of

descematoceles because exposed descemets membrane in the centre does not stain

(Kern 1990). Varying degree of corneal opacity results from stromal and epithelial

edema and infiltration by inflammatory cells into the affected area (Kern 1990). On

the basis of clinical ophthalmic examination and fluorescein staining, nature of

corneal ulceration was classified as superficial (n=8) and deep (n=13).

4.2.3 Neuro-ophthalmic reflexes: In the present study 38.09% (n=8) of the animals

showed positive for menace and pupillary light reaction (PLR) who had

comparatively small, superficial ulcers with almost negligible corneal opacity.

Sluggish menace reflex was observed in 42.85% (n=9). Pupillary light reaction (PLR)

could not be ascertain due to extensive corneal opacity in majority of the dogs. while

as in 19.04% (n=4) dogs had negative menace reflex. PLR in these dogs could not be

ascertained because of extensive corneal opacity (Cullen and Grahn 2005).

4.2.4 Surgical management of corneal ulceration: Corneal erosions provide a

therapeutic challenge to the ophthalmologists. A large number of therapies have been

suggested with variable success rates (Stanley et al 1998). The therapy of choice is

based on clinical signs, ophthalmological tests and the efforts to be made by the

owner. In treating corneal ulceration, the most important step is to determine and

eliminate the cause, followed by attempts to create an ideal environment for lesion

repair, prevention of progression, and surgical treatment to prevent corneal rupture

(Rebhun 1983). Treatments used for corneal ulcers include surgical epithelial

debridement, including mechanical or chemical corneal debridement, grid or punctate

keratotomy, keratectomy, conjunctival grafting, conjunctival pedicle grafting and

medical management, which may include anti protease and antibiotic agents (Stanley

et al 1998).

Group I A (Corneal scarification only): In group II A (n=8) corneal scarification

was done by two methods i.e multiple punctate keratotomy (MPK) and grid

keratotomy (GK) performed in 4 dogs each. After performing the multiple punctate

keratotomy (MPK), temporary tarsorrhaphy was done and sutures were removed after

7 days. Out of the 4 eyes with ulcers, 2 eyes had healed completely and regained

61

proper vision and in remaining 2 eyes ulcer did not healed completely and there was

corneal opacity at 7th

post operative day (Fig 46). Overall surgical outcome with the

punctate keratotomy was healing in 2/4 eyes (50%), and 2/4 (50%) eyes has opacity

on ulcer area on the day of presentation. Champagne and Munger (1992) performed

multiple punctate keratotomy (MPK) in 18 dogs with persistent corneal erosions. It

was concluded that 88% healed within 2 weeks, however, it was not possible to

determine whether any of these cases had been attributable to corneal endothelial

dystrophy that characteristically presents with varying degrees of diffuse corneal

oedema. Grid keratotomy (GK) was also performed in 4 dogs and tarsorrhaphy was

also done and sutures were removed after 7 days. Moore (2003) described that grid

keratotomy involves incision of the cornea at 1–2 mm intervals over the ulcerated

area, including 1–2 mm beyond the periphery of the lesion. All eyes healed with

restoration of vision on 7th

day (Fig 47). Success rate in grid keratotomy was high

100% as compared to 50% in punctate keratotomy (Singh et al 2014, Stanley et al

1998, Hollingsworth et al 1992).

Grid keratotomy (GK) offers a high rate of success in healing primary

persistent corneal ulcers. This technique is superior and provide much faster healing

than those previously described. Grid keratotomy exposes the migrating corneal

epithelial cells to the sub epithelial type I collagen. Contact of the migrating epithelial

cells with the type I collagen in the anterior stroma is believed to result in the more

effective attachment between epithelium and stroma. There is an extremely complex

relationship between the basal cell layer of the corneal epithelium, its basement

membrane and the superficial layers of the underlying stroma (Moore 2003). This

relationship includes an adhesion complex involving keratin filaments,

hemidesmosomes, anchoring filaments from the hemidesmosomes to the basement

membrane, and fibrils from the basement membrane to the anterior stroma (Pickett

1995). When injury occurs to the corneal epithelium, extracellular matrix proteins

such as fibronectin and laminin play a role in adhesion of newly migrated epithelial

cells to underlying extracellular matrix (Champagne and Munger 1992). These

adhesion points or focal contacts take the place of hemidesmosomes in this early

phase of healing. There is a paucity of hemidesmosomes at the site of the non

adherent or loosely adherent corneal epithelium in cases of corneal ulcer (Janssens

2007).

62

For a surgical technique to be effective, cornea needs to be treated at least to

the depth of the epithelial basement membrane (Kirschner 1990). Grid keratotomy

penetrate deeper than this in to the cornea. There is speculation that the basement

membrane thickening may cause the persistent corneal ulcers. It has been proposed

that there may have been changes in the biochemical composition of the basement

membrane that could inhibit normal binding and function (Kirschner et al 1989).

Cook and Wilcock (1995) described the presence of a thin superficial acellular zone

of hyalin collagen in the corneal stroma. This hyalin collagen was absent in healed

cornea, and it has been proposed that this hyalin collagen acts as barrier to epithelial

adhesion. Grid keratotomy breaches and exposes this hyalinised zone, and this may

account for the higher healing rates of this technique compared with others (Peiffer et

al 1976). Success rate with grid keratotomy in the present study might be due to the

fact that grid keratotomy exposed large stroma which allowed stronger adhesions than

with multiple punctate keratotomy. It is also possible that multiple punctate

keratotomy is less effective in breaching the hyalinised zone that acts as barrier to

epithelial adhesion (Gelatt and Samuelson 1982).

Group II B (Corneal scarification and conjuctival grafting): In group II B (n=5),

corneal scarification and conjuctival grafting was done. Corneal scarification was

done either by multiple punctate keratotomy or grid keratotomy followed by

conjunctival grafting after that third eye lid flap was made followed by tarsorrhaphy.

The sutures were removed on 15th

day and surgical outcome was accessed. Out of 5

eyes with ulcer, 4 eyes had healed and regain proper vision with a small scar on ulcer

site while in the remaining eye healing had not occurred and there was extensive

corneal opacity. Success rate with this surgical technique was 80% (4/5). Eyes with

healed corneal ulcer were put only on post operative medication and were further

accessed on 30th

post operative day. Three eyes among the healed corneal ulcer had

scar on 30th

post operative day while the remaining one could not be accessed because

owner did not revisit for ophthalmic examination of the dog. Dorbandt et al (2015)

used conjuctival graft along with an acellular submucosa implant with a successful

outcome in 87% of eyes. A number of surgical techniques have been described for

the management of deep ulcers (Roberts 1953). In dogs, cats, and horses with deep

ulceration, frozen lamellar corneal grafts, porcine small intestinal sub mucosal grafts,

amniotic membrane grafts, and cyanoacrylate glue, among other materials, have been

Fig. 45: Photograph showing both dorsonasal

and ventronasal Ulcer in a dog

Fig. 46: Photograph showing slight Corneal

Opacity on 7th

post operative day undergone

multiple punctate keratotomy

Fig. 47: Photograph showing complete healed

Cornea on 7th

post operative day undergone

grid keratotomy

63

evaluated with good results, and Conjuctival grafts are also frequently used (Hyman

et al 2004). Similar techniques have also been used in humans, often as temporary

measures prior to definitive penetrating keratoplasty.

Group II C (Conjuctival grafting only): In group II C (n=8), conjuctival grafting

was done alone in eyes having deep corneal ulcers. In one eye descemetocele was

present. Third eye lid flap was made along with tarsorrhaphy. Sutures were removed

after 15 days for assessment of surgical out come. Out of 8 eyes, 7 had healed and

regained vision with scar and corneal opacity at 15th

post operative day (Fig 48).

These eyes were again accessed after 30th

post operative day. Corneal opacity had

subsided but scar remained up to last day of evaluation (Fig 49). Complications

observed postoperatively in the present study included corneal scar at the ulcer site,

corneal vascularization and corneal pigmentation (Roberts 1953). In one eye ulcer did

not heal, the age of that dog was 8 years that may had been the reason for non healing

of the ulcer (Mc Neil 1997). Deep ulcerative keratitis and deep stromal ulcers are

frequently seen in brachiocephalic breeds and are usually present as a central and/or

paracentral ulcers with rapid onset (Moore 2003). Recurrent corneal erosions,

descemetocoeles, staphylomas and feline sequestrations are also commonly found

conditions in small animal clinical practice (McNeil 1997). Success rate with

conjuctival grafting was 87.5% (7/8). However, success rate in the present study was

comparatively lower than previous study by Wilkie and Whittaker (1997). Dorbandt et

al (2015) used conjuctival flap method for the management of corneal perforations in

canines and achieved a success rate of 97%. Objectives for the surgical treatment of

deep corneal ulcers are: preservation of corneal integrity, minimizing lesions

incompatible with functional vision and replacement of lost corneal tissue (Morgan

and Abrams 1994). The use of conjunctival grafts for corneal perforations

accomplished these goals. The increased blood supply to the healing cornea is an

added benefit not obtained by other procedures such as lamellar corneo scleral

transposition or full thickness corneal graft (Wilkie and Whittaker 1997). Furthermore

the aim of the graft is to cover the defect and its closest surroundings, achieving

conjunctival to corneal epithelium cell apposition over as much of the graft

circumference as possible. Conjuctival graft allows edge to edge apposition of the

graft margin and will ensure rapid acceptance of the graft, epithelial cell contact

64

inhibition and cell to cell adherence and minimize scar formation (Wilkie and

Whittaker 1997).

4.2.5 Complications: In the present study, the most common postoperative

complication was the breakage of the conjuctival graft in both group II B and group II

C, but breakage of the graft did not hamper the healing of corneal ulceration.

Complications observed postoperatively are numerous with conjuctival grafting which

includes corneal fibrosis at the site of injury, corneal vascularisation, corneal scar

formation, corneal pigmentation, and recurrent corneal ulceration (Tuntivanich and

Tuntivanich 2007). However, none of these factors significantly affected visual

outcome or success rate (Sandberg et al 2012). It has been previously established that

disruption of the intraocular environment may lead to pre-iridial fibrovascular

membrane formation with subsequent development of glaucoma (Zarfoss et al 2010)

but glaucoma was not an observed post surgical complication in the present study

study.

Fig. 48: Photograph showing scar and blood

vessels on 15th

post operative day undergone

conjunctival grafting

Fig. 49: Photograph showing scar on 30

th post

operative day undergone conjunctival grafting

CHAPTER V

SUMMARY

The present clinical study was conducted on 27 canine cataract cases in 23

dogs and 21 corneal ulcer cases in 21 dogs with history of vision abnormalities,

reported at Department of Veterinary Surgery and Radiology, GADVASU, Ludhiana.

The clinical cases were divided in two groups i.e Group I (n=27) which consisted

canine cataract cases and Group II (n=21) that consisted of canine corneal ulcer cases.

Group I was further subdivided in to Group I A (n=5) in which rigid

Polymethylmethacrylate (PMMA) lens was implanted after phacoemulsification and

Group I B (n=22) in which foldable square edge acrylic lens was implanted after

phacoemulsification. Group II was also sub divided in to Group II A (n=8) in which

corneal scarification technique was used, Group II B (n=5) in which both corneal

scarification and conjunctival grafting was used and Group II C (n=8) in which only

conjunctival grafting was used.

Age wise distribution of animals suffering from cataract showed involvement

of mostly middle aged animals. Sex wise distribution of animals suffering from

cataract showed high incidence in males. Breed wise distribution showed high

incidence in German shepherd followed by Labrador.

The present study indicated senility (n=22) and diabetes (n=4) as the causative

factor for the development of bilateral cataract. Stage of cataract in the present study

was mature (n=25), followed by immature cataract (n=2).

All the animals of group I (Cataract) were subjected to visual examination by

evaluating for different reflexes; menace, pupillary light reflex, obstacle course test,

Schirmer‟s tear test, tonometry, direct and indirect ophthalmoscopy, and ocular

biometric analysis which included A-mode ultrasonography and Pachymetry for

evaluation of the different segments of eyes and to check the possibility of retinal

diseases and optic nerve pathology. Routine haematological and biochemical

examinations were also performed in all cases.

Pre-operative treatment regimes included initiation of topical broad spectrum

antibiotics and instillation of 1% tropicamide and atropine eye drops 30 minutes prior

to surgery that achieved satisfactory pupillary dilatation and facilitated lens

66

manipulation during surgery. Coaxial binaocular operating microscope was used

during operative procedure. Premedication was done by combination of Butorphenol

@0.2mg/kg, Glycopyrolate @ 0.01mg/kg and Acepromazine 0.05 mg/kg body

weight (IM). General anaesthesia was induced using Ketamine @ 5mg/kg and

Diazepam @0.5mg/kg body weight (IV), and maintained using 2% Isoflurane.

For surgical management of group I (Cataract) dogs were secured in lateral

recumbency with the affected eye placed dorsally and head positioned by placing soft

padding below the muzzle. The surgical procedures performed were standard for both

sub groups. One handed phacoemulsification technique was performed through a 2.8

mm clear corneal incision. Intracameral adrenaline was administered intra-operatively

to effect mydriasis. The anterior chamber was reformed using hydroxypropyl methyl

cellulose 2%. Balanced salt solution (BSS) was used for irrigation and aspiration

during the procedure. The Curvilinear capsulorhexis was performed using 26 G

double bend hypodermic needle. The incision in group I A was enlarged to

accommodate the single piece non foldable PMMA intraocular lens. The corneal

incision was closed using 6-0 ophthalmic Polyglactin 910 suture material. In group I

B, incision was closed by stromal hydration after implantation of foldable square edge

acrylic lens.

Post-operative visual activity was assessed using visual function tests. Intra

operative complications included hyphema and pupillary constriction. Post-operative

complications observed were corneal opacity, uveitis and transitory corneal edema in

all cases.

In case of phacoemulsification and IOL implantation 20% and 68 % success

rate was observed in group I A and group I B, respectively.

In group II, animals suffering from corneal ulceration showed that young male

animals had high rate incidence of corneal ulcer due to their most active life period, so

corneal traumatic injury was most prevalent in young animals. Breed wise distribution

showed that the most affected breed was male Pug dogs.

In present study the commonest cause of corneal ulceration was

lagophthalmos (n=17) followed by trauma (n=4) and the most common symptoms

67

were conjuctival hyperemia, corneal opacity and varying degree of corneal oedema.

The location of ulcer was central (n=12), dorsonasal (n=5) and ventronasal (n=4).

Pre operatively all the animals were subjected to visual examination by

evaluating the menace, pupillary light reflex, Schirmer‟s tear test, tonometry and

Fluorescein dye test to check the integrity of optic nerve. Routine

haematobiochemical parameters were studied in all the dogs. Except in one eye, the

mean IOP was normal in all the cases. All unhealthy corneas stained greenish with

fluorescein dye and the ulcers were diagnoses as superficial (group II A) and deep

(group II B and group II C).

Treatment regimes were started pre operatively by using topical broad

spectrum antibiotic Gentamicin and Carboxy methyl cellulose sodium lubricant drops

were started 30 minutes before surgery. Operation was performed under similar

combination that was used for cataract operation.

All the dogs were secured in lateral recumbency with the affected eye placed

dorsally and head positioned by placing soft padding below the muzzle and rest of the

body was covered with surgical drapes. The antisepsis was achieved by using normal

saline and diluted povidone iodine solution. The surgical procedures performed were

corneal scarification either by grid keratotomy and multiple punctate keratotomy in

group II A. In group II B corneal scarification and conjuctival grafting was done and

in group II C, conjuctival grafting alone was done and surgical outcome was accessed.

In group II A, complete healing of corneal ulcers in all cases was seen in eyes

that had undergone grid keratotomy on 7th

postoperative day while as a success rate of

50% was observed in eyes that had undergone multiple punctate keratotomy. In group

II B, overall 80 % success rate was observed on 15th

postoperative day with scar and

corneal opacity. In group II C, over all 87.5% success rate was achieved with

conjuctival grafting alone on 15th

post operative day. In one case with descemetocoele

100% healing occurred with conjuctival grafting but scar remained up to the 30th

day

after last day of presentation of the case.

Most common post operative complication in group II B and II C was

breakage of grafts, formation of scar and corneal opacity.

68

The following conclusions were drawn from the present study:

Phacoemulsification with implantation of foldable square edge acrylic IOL

resulted in a shorter healing process, fewer complications, more rapid

visual recovery and a higher success rate than phacoemulsification with

rigid IOL implantation in mature cataracts.

A- mode ultrasonography and Pachymetry were helpful in assessment of

different ocular parts and health status of cornea respectively in cataract

affected eyes.

Corneal ulceration is the common ophthalmic disease of young Pug dogs

and lagophthalmos followed by traumatic injury was the common cause

for the development of corneal ulceration.

Grid keratotomy was better for the management of superficial corneal

ulcers than multiple punctate keratotomy with high success rate and early

healing.

Conjuctival grafting with corneal scarification and conjuctival grafting

alone were equally helpful in management of deep corneal ulcers.

Scar formation and corneal opacity were observed as major post operative

complications after both conjuctival grafting alone and conjuctival grafting

and scarification techniques.

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VITA _____________________________________________________________________

Name of the student : RAYEES AHMAD RATHER

Father‟s name : Mr. Mohmad Ahsan Rather

Mother‟s name : Miss Raja Banoo

Nationality : Indian

Date of Birth : 30-12-1984

Permanent Address : Mahind Srigufwara. District Anantnag Jammu &

Kashmir - 192401

EDUCATIONAL QUALIFICATION

Bachelor‟s Degree : B.V.Sc & A.H

University : J.N.K.V.V Jabalpur (M.P)

Year of Award : 2008

OGPA : 7.0/10.00

Master‟s Degree : M.V.Sc (Veterinary Surgery and Radiology)

University : R.V.S.K.V.V. Gwalior (M.P)

Year of Award : 2010

OGPA : 8.18/10.00

Title of Thesis : Comparative Evaluation of Epidural Effects of

Bupivacaine, Ropivacaine and Ropivacaine –

Xylazine combination in Goats

Ph.D : Ph.D (Veterinary Surgery and Radiology)

OGPA : 8.0/10.00

Awards/Distinction/ :

Fellowship/Scholarship