Preface to fifth edition

I extend my sincere thanks for the valuable support expressed by students of Ophthalmology for my book. The book has been regularly updated keeping pace with recent developments at the same time retaining its simplicity. In the current edition, management of angle closure glaucoma, retinal detachment, hypertensive retinopathy, description of cataract surgery, refraction, ocular trauma have been revised. Treatment of ocular tumors and infections has also been updated. Several new photographs and illustrations are added to make understanding easier. Modern advances including collagen cross linking, argon and selective laser trabeculoplasty have been added.

The simple and systematic presentation that has made the earlier edition so popular has been retained. The clear language and tabular columns should help the students in retaining key points.

I believe that both post-graduate and undergraduate students of ophthalmology will find this book helpful. I hope the fifth edition enjoys the same degree of popularity as the previous editions.

Pg 66 table

S No Trachoma Spring Catarrh1 Age All age Young persons 6-20 yrs2 Seasonal Variation Absent Seen in summer and spring3 Itching Absent Marked2 Follicle Upper lid and

upper fornixAbsent

3 Papillae Small, upper lid and fornix

Small to large with cobblestone appearance. Upper lid-palpebral formBulbar conj.-limbal form

4 Pannus Present Rarely present

Pg 67 Treatment of Trachoma

1) Topical treatment – erythromycin (or) tetracycline eye ointment. In trachoma control programme it is given for 5 days a month for 12 months.

2) Oral therapy – Tetracycline, doxycycline, clarithromycin and azithromycin ar effective. Tetracycline- 250-500mg QID for 3-6 weeksErythromycin – 250-500mg QID for 3-6 weeksClarithromycin – 250-500mg QID for 3-6 weeksDoxycycline – 100mg BD for 3-6 weeksAzithromycin – single dose treatment with 1g

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Pg 73Treatment

Sunglasses, Crookes’B1 or B2 glasses protect the eye from ultraviolet ray, dust, wind thus preventing progression or recurrence of pterygium.

When the pterygium is stationary no treatment is necessary. When the apex of the pterygium lies over the visual axis (opposite the pupillary area), it is better to allow it to grow and remove it at a later date. The apex of pterygium is most densely adherent to the cornea and on removal leaves a permanent scar.Surgical Treatment

Bare Sclera Technique The neck of the pterygium is grasped with fixation forceps The head of the pterygium is shaved from the cornea with Bard-

Parker knife No. 15. It is then freed from the sclera for about half the distance from the

canthus and excised The bare area of sclera after removal of pterygium is left behind This bare area of sclera acts as a barrier for recurrence

After excision of pterygium recurrences are common. Hence excision should not be done in every case.

Methods to prevent recurrence1. Postoperative use of corticosteroid drops 2. Application of antimitotic drug intraoperatively on the bare sclera (mitomycin

C - 0.02-0.04 %) for 1 to 2 minutes.3. Use of antimitotic drug (mitomycin C 0.2-0.04%) eyedrops TDS for a month.4. The bare area of sclera is covered by amniotic membrane graft.5. Bare sclera covered by conjunctival autograft from the superotemporal

quadrant or superior/inferior limbal area from the same eye.

Pg 87(i) Broad spectrum antibiotics covering both gram positive and negative organisms re started before culture sensitivity report. The commonly used drugs are:

- Fluroquinolones – 0.3% Ciprofloxacin - 0.3% Ofloxacin - 0.3% Gatifloxacin - 0.1% Moxifloxacin

Or combination of fortified antibiotics constituted from injection vial used for parenteral use.

- Vancomycin 50mg/ml + Cefazolin 50mg/ml

Pg 97^Occurs as a result of immune reaction to toxins produced by staphylococcal organisms in lid or conjunctiva

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Pg98Treatment

1. Excision of a 4-7mm strip of adjacent conjunctiva (peritomy) may prove successful by eliminating conjunctival source of enzyme collagenase and proteoglycanase.

2. Bandage contact lens.3. Topical corticosteroids or cyclosporine eyedrop.4. Oral steroids.5. Systemic immunosuppresants like cyclosporine, azathioprine or

cyclophosphamide.

Pg 110 3) Corneal Collagen Cross-linking with Riboflavin – Ultraviolet radiation in

combination with riboflavin initiates molecular cross linking of corneal collagen. Thus progression of keratoconus is slowed down or stopped.

pg123Iris crypts are depressions on the surface of ciliary zone where the superficial layer of iris is missing. It is arranged in two rows, peripheral crypt near the iris root and central crypt near the collaratte. Crypts are blurred and indistinct (muddy iris) in iridocyclitis. Crypts are the preferred site for laser iridotomy as the iris tissue is relatively thin there facilitating easy penetration by laser energy.

Pg 126 Etiology – In most cases it remains obscureClassification

Blunt injury Sympathetic Ophthalmitis Penetrating injury

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Inflammatory 3. Traumatic

1. Immune related 2. Infective

Endogenous infectionSecondary infection Exogenous infection

- Hypersentivity to bacterial antigens eg. TB

- Hypersensitivity to lens proteins

- Hypersensitivity to uveal pigments

1. Immune relateda. Hypersensitivity to bacterial antigens

i. TB – usually of lungs, lymph nodesii. Streptococci – teeth, tonsils, sinuses, urogenital tract. Primary

source of infection exists at these sites. At one time the infection was generalized by the escape of organisms into the blood stream when the ocular tissues – uvea had become sensitized to them. At a later date further dissemination of the organisms or their proteins meeting the sensitized uveal tissue excites an allergic response.

b. Hypersensitivity to lens proteins – phako-anaphylactic reaction. They have also a toxic action on the iris.

c. Hypersensitivity to uveal pigments – sympathetic ophthalmitis.

2. Infectivea. Endogenous – organisms primarily lodged in some other organ of the

body reach the eye through the blood stream. i. Viral – herpes simplex, herpes zoster, measles, mumps, rubella

ii. Bacterial – tuberculosis, syphilis, leprosy, gonorrhoea, brucellosisiii. Fungal – histoplasmosis, aspergillosis, candida albicans,

mucormycosisiv. Protozoa – toxoplasmosisv. Nematodes – ankylostomiasis, filariasis

b. Secondary – due to spread from one or other of the ocular tissues – corneal ulcer, scleritis.

c. Exogenous – the organisms reach the eye form outsidei. Perforating injury

ii. Perforated corneal ulceriii. Intraocular operation

3. Idiopathic a. Sarcoidosis b. Vogt-Koyanagi-Harada’s diseasec. Behcet’s diseased. Ankylosing spondylitise. Rheumatoid arthritis

4. Traumatica. Blunt b. Sympathetic ophthalmitis

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Pg 143 *Local antibiotics

1. Fortified Vancomycin (50mg/ml) + Fortified Ceftazidime (50mg/ml) eyedrops instilled every one hour

2. Gatifloxacin 0.3% or Moxifloxacin 0.1% eyedrops every one hour instillationSystemic antibiotics

1. Intravenous Cloxacillin in combination with Gentamicin or Ceftazidime/Ceftrioxone. In case of infection with Methicillin Resistant Staphylococcus aureus (MRSA), Vancomycin is preferred to cloxacillin.

2. Broad spectrum Fluoroquinolones, Ciprofloxacin 200mg IV BD is given

Pg149*MANAGEMENT OF DEVELOPMENTAL CATARACT

I. Medical Treatment:1. Prescription of glasses if necessary2. Mydriatics – this is particularly useful in cases where there is a central

dense opacity with a relatively clear periphery. i. 10% phenylephrine 3 or 4 times a day. With this accommodation is

retained. ii. 1% atropine or 1% tropicamide drops in younger children

II. Optical iridectomy – was done earlierIII. Surgery on lens: operation on the lens should not be performed if vision is 6/12 or

even 6/18. this vision with retained accommodation is to be preferred to probably improved vision after operation without accommodation.

Age at which a child should be operated:It is preferable to wait until the child is 2 years of age, so that the eyeball is bigger

and the anterior chamber is deeper. However surgery is indicated early before fixation and binocularity develops to prevent development of amblyopia. Early surgery is especially indicated when:

a) there is total cataractb) pupil will not dilate with atropinec) squint or nystagmus is developing

Preoperatively it is imperative that full mydriasis be achieved with 1% atropine. This should be maintained post operatively for atleast 2 months to avoid complications. When operated before two years of age intraocular lens is not placed and visual rehabilitation is by means of spectacles or contact lens. Intraocular lens is placed as a secondary procedure after two years of age when the eyeball would have grown to adult size.

Surgical options for paediatric cataractPediatric cataract surgery differs from adult cataract in the following aspects:

a. The cataract is soft and can be aspirated with irrigation-aspiration cannula or phacoaspiration

b. The capsule is elastic hence capsulotomy is difficultc. There is frequent fish mouthing of incision requiring suturing of section

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d. Formation of posterior capsule opacification is nearly 100%e. Acrylic intraocular lens is preferred as it reduces postoperative

inflammation and reduces posterior capsular opacification

1. Lensectomy and anterior vitrectomy technique (LAV)This is performed using a VISC probe (vitreous infusion suction cutter). The

probe is introduced via the pars plana. The cutter helps to fragment the lens into small pieces which are then aspirated through the suction part. Infusion of fluid helps to maintain the anterior chamber and prevent it from collapsing. All the three functions take place simultaneously. Anterior vitrectomy is also routinely carried out.

This technique provides a clear visual axis but needs rehabilitation of aphakia by use of spectacle or contact lens. As the lens with its capsular bag is removed it does not allow the option of placement of posterior chamber intraocular lens. Hence this technique is loosing ground to phacoaspiration.

2. Phacoaspiration with primary posterior capsulotomy - this is the most widely accepted technique today. The main aim of the surgical technique is to provide long term clear visual axis and visual rehabilitation.

a. Clears the visual axis by removing the cataractb. Prevents posterior capsule opacification by doing a primary posterior

capsulotomyc. Aids in in-the-bag placement of intraocular lens

Pg 154Phacomorphic Glaucoma

Phacolytic Glaucoma

Phacotoxic Uveitis

Phacoanaphylactic Uveitis

Anterior chamber depth

Shallow Normal or Deep

Deep due to posterior synechiae

Deep due to posterior synechiae

IOP Markedly increased

Increased Initially normal

Normal/ increased

Pupil Mid dilated not reacting

Mid dilated reacting to light

Small irregular sluggish reaction to light

Small irregular sluggish reaction to light.

Cells/ KP’s Absent Absent Present Small KP’s

Present KP’s may be large.

Gonioscopy Closed Open Initially open later may be closed due to peripheral anterior synechiae

Open/ synechial closure

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*pg159 Treatment:

Subluxated lens – concave or convex lenses may be tried to improve vision. Subluxated lens when vision does not improve with spectacles or when it is cataractous surgical intervention is required. When the degree of zonular dialysis is less than 90-180 degrees, cataract surgery is aided by using endocapsular ring to stabilize the capsular bag. The intraocular lens is then placed in the bag. When the zonular dialysis is more than 180 degrees intracapsular cataract extraction (lens is removed in toto with its capsular bag) using wire vectis and scleral fixation of intraocular lens is done.

Dislocated lens:Anterior dislocation – the dislocated lens in the anterior chamber is removed

using wire vectis.

Posterior dislocation – posterioly dislocated lens needs to be removed as it may lead to uveitis or secondary glaucoma.Technique:

Three port pars plana incisions are made (refer Pg ). Complete vitrectomy is done to free the dislocated lens from surrounding vitreous. Once vitrectomy is completed the dislocated lens is removed using one of the 2 techniques.

1. The lens is impaled with MVR (microvitreoretinal) blade and lifted up into the anterior chamber through the pupil. The lens is then delivered out through a limbal section using wire vectis.

2. Perfluorocarbon liquid is used to float the dislocated lens anteriorly. It is then removed using wire vectis through limbal section.

3.Since there is no capsular support in dislocated lens, anterior chamber lens may be implanted or scleral fixation of intraocular lens is done.

Pg 177*Automated perimeters provide quantifiable data which can be subjected to

statistical analysis. The threshold detection is very sensitive. Helps in storing and comparing successive field of a patient.

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Pg 180*S

NoArgon laser trabeculoplasty (ALT) Selective laser trabeculoplasty (SLT)

1. Mechanism of action

Thermal energy produced by absorption of laser by pigmented trabecular meshwork causes shrinkage of collagen of the trabecular lamellae. This probably opens up intertrabecular spaces in untreated region and expands the Schlemn’s canal by pulling the meshwork centrally (trabecular tightening)

SLT is based on the principle of photothermolysis. It uses a specific wavelength that selectively targets the pigmented trabecular meshwork without causing a coagulative/thermal damage to adjacent non pigmented trabecular meshwork. It uses frequency doubled Nd-YAG laser. (wavelength-532nm)

2 Technique Aiming beam is focused at the junction of pigmented and non-pigmented trabecular meshwork. Transient blanching of trabecular meshwork or appearance of minute gas bubble. 40-50 laser burns over 180 degree

With SLT there is no visible blanching to gauge the endpoint as seen with ALT. the procedure is initially started with 0.8mJ at 6 or 12o’clock and if bubble formation occurs the energy is decreased in 0.1mj steps till no more bubble formation occurs. The procedure is completed with that power. 40-50 laser burns over 180 degrees

3 IOP reduction

Same in both techniques

Advantage of SLT over ALT: In SLT the surrounding tissue is undamaged. Therefore unlike ALT it is potentially repeatable procedure because it does not cause any coagulation damage to the trabecular meshwork. It can also be performed in the eyes with previously failed ALT. Repeat treatment with ALT is generally avoided due to its damaging nature.

Pg 182Clinical features

The course of the disease may best divided into 5 stages.

1. PRIMARY ANGLE CLOSURE SUSPECTThese patients are asymptomatic and are identified during routine eye

examination. Signs

1. Shallow anterior chamber2. Occludable angle – in atleast 270 degrees of angle the trabecular meshwork is

not visualized through a gonioscope3. Positive provocative test ie. Precipitates an angle closure attack

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a. Mydriatic test: The pupil is dilated with 10% phenylepherine or 2% homatropine. If the tension rises more than 8mm Hg the rest is positive.

b. Dark room test: The patient is kept in dark room for half an hour so that the pupil dilates. If the tension rises more than 8mm of Hg the test is positive. It is important to impress on the patient not to fall asleep since sleep causes miosis of pupil.

1. SUBACUTE or INTERMITENT PRIMARY ANGLE CLOSURE GLAUCOMACommonly occurs in dim illumination and resolves spontaneously.

Symptoms Blurring of vision Colored halos around lights due to corneal edema Mild eyeache/headache

Signs Eye is white Cornea is hazy due to edema IOP is raised

Treatment1. Pilocarpine drops 2% TDS, it constricts the pupil and prevents crowding of iris at

the angle2. Laser iridotomy – helps the aqueous humor to pass directly into AC from

posterior chamber thereby overcoming the pupillary block. Iridotomy using Nd YAG laser is being preferred over surgical peripheral iridectomy. Laser iridotomy is done in the superotemporal or superonasal periphery, preferably in an iris crypt. Advantages:

- non-invasive- outpatient procedure- reduces surgical complications such as cataract and endophthalmitis

Disadvantages:- transient IOP rise- iritis- bleeding

3. Surgical – peripheral iridectomy.

3. ACUTE PRIMARY ANGLE CLOSURE GLAUCOMAIn a considerable number of cases both eyes are affected almost simultaneously,

an attack in one eye being followed by similar tragedy in the other. Symptoms1. Sudden gross diminision of vision: in a few hours it may be reduced to hand

movements close to face or even to perception of light.2. Severe neuralgic pain in the eye radiating along the branches of the 5th cranial

nerve and causing violent headache, this pain sometimes is so severe that it is associated with nausea and vomiting. Such attacks have been mistaken for “bilious attacks” or acute abdomen.

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3. Watering Signs1. Oedema of lids2. Marked congestion of the conjunctiva – both ciliary and conjunctival; chemosis of

conjunctiva3. cornea is steamy and insensitive4. AC is shallow5. Pupil is dilated, vertically oval. Reaction to light and accommodation are absent. 6. Iris is congested and discolored7. IOP is markedly raised and eyeball is stony hard8. Fundus examination with an ophthalmoscope is not possible due to corneal

oedema. The oedema may be temporarily cleared with glycerine drops. Fundus shows the picture of papilledema – disc margins are blurred, hyperemic, physiological cup is obliterated. Arterial pulsations are seen.

Differential diagnosis – Refer acute iridocyclitis

Medical treatment Every effort should be made to lower the tension by medical means before operating in order to avoid:

i. The difficulties of operation (marked bleeding) on a congested eyeii. Danger of expulsive hemorrhage (refer)

1. Rapid reduction of the acutely raised IOP. It is usually above 40mmHg Hyperosmotic agents – they cause deturgescence of vitreous (by

withdrawing fluid from it) and lowers the intraocular pressure. i. IV Mannitol (20%) – 1-2g/kg body weight (avoided in patients

with borderline congestive cardiac failure)ii. Glycerol (50%) – 1 oz TID. (avoided in diabetics)

iii. Oral Isosorbide 1 oz TID (can be given in diabetics) Tab. Acetazolamide – carbonic anhydrase inhibitor which reduces

aqueous formation. Dose – 250mg QID.2. Intensive miotic therapy – the most important medical objective is establishment

of miosis thus pulling the congested root of iris out of the angle. 2% pilocarpine drops instilled every 5 min for half an hour followed by half hourly interval until miosis occurs.

3. Analgesics – to relieve pain. Tab ibuprofen or injection diclofenac or inj. Pethidine. Intramuscular or subcutaneous injection of Morphine (10-16mg) supplements miotic effect as well as relieves pain.

Laser treatment Laser iridotomy – done using Nd-YAG laser to relieve pupillary block once the

cornea clears and IOP comes below 30mmHg. Gonioscopy is done prior to laser iridotomy to assess angle status. If synechial closure is less than 180 degrees, laser iridotomy is usually successful and relives the pupillary block. Even in the presence of 360 degrees synechial closure “trial of laser iridotomy” is done as it is a non-invasive procedure and it may open up the angle to some extent and bring down the

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intraocular pressure. After laser iridotomy gonioscopy is done again to assess angle status. If angles still remain closed and intraocular pressure doesn’t come down surgical modality of treatment is planned for.

Surgical treatment1. Surgical peripheral iridectomy – performed when laser treatment is difficult due

to hazy cornea. However such a situation is rarely encountered in clinical practice. 2. Trabeculectomy – done when peripheral anterior synechiae are extensive and IOP

doesn’t fall inspite of laser iridotomy. NB. If only one eye is affected prophylactic laser iridotomy (or) peripheral iridectomy should be done in the other eye.

4. CHRONIC PRIMARY ANGLE CLOSURE GLAUCOMAAfter a period of quiescence, another acute attack occurs, succeeded by others,

each attack causes greater reduction of vision and permanent adhesion of the congested root of iris to the back of the cornea – peripheral anterior synechiae. If the peripheral anterior synechiae become extensive, the tension remains permanently elevated. This is the stage of chronic congestive glaucoma. Signs:1. Ciliary congestion2. Corneal haze3. Pupil semi-dilated and sluggishly reacting4. IOP is raised5. Fundus examination shows glaucomatous cupping6. Field defect appears – similar to those in chronic simple glaucoma (refer)

Treatment1. Medical

a. Miotic: 2% pilocarpine dropsb. Tab. Acetazolamide 250mg tds or qid

2. SurgicalFiltering operation – trabeculectomy

5. ABSOLUTE GLAUCOMA It is the end stage and characterized by

1. Absence of perception of light2. High IOP

Pg 187Treatment – since the modern trend is to preserve the eyeball for cosmesis, measure to reduce the intraocular pressure by cyclodestructive procedures is tried before considering enucleation.

1. Cyclodestructive procedure - tension may be lowered by cyclocryotherapy or cyclophotocoagulation. Cyclocryotherapy reduces aqueous formation by inducing segmental atrophy of ciliary body by application of cryo on the overlying sclera. Cyclophotocoagulation is delivered using Nd-YAG or diode laser fibreoptic probe

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placed over the sclera. Laser induced destruction of the ciliary epithelium and its blood vessels reduce aqueous formation.

2. Enucleation – since the eyeball is blind and painfulPg 200 ^ affecting the retinal capillary bed* Capillary changes consists of

- loss of pericytes- thickening of basement membrane- proliferation of endothelial cells

Histological changes include - deformation and increased rouleaux formation of red blood cells- increased platelet stickiness and aggregation leading to decreased transport

of oxygen* Other risk factors include poor metabolic control, hypertension, nephropathy, anaemia, smoking, hyperlipidemia, pregnancy, obesity

Pg202*ii) IRMA

Intra Retinal Microvascular Abnormalities are opening of preexisting channels that run from retinal arterioles to venules, by-passing the capillary bed. These shunts open up adjacent to areas of capillary closure to supply oxygen to hypoperfused retina.

Pg 204Hypertensive retinopathy

Hypertension may be primary (essential) or secondary as in renal hypertension, toxemia of pregnancy etc. Hypertension can result in significant ocular morbidity many of which are acute and catastrophic events.

Eye is an end arteriolar system and is therefore susceptible to changes in blood pressure. It provides a window to visualize blood vessel abnormalities directly, allowing us to identify patients who are at a higher risk for developing coronary, carotid ad cerebrovascular ischemic events.

Pathology The vascular changes in retina associated with elevated arterial pressure due to

any cause depend on the resilience of vessels and the duration of hypertension. The essential vascular change is hypertrophy of the tunica media followed by fibrosis and hyalinization leading to narrowing of the lumen. Other ocular morbidities associated with hypertension includes

2. Central retinal artery occlusion (CRAO) – two thirds of all patients with CRAO have associated systemic hypertension. (Refer pg. 207)

3. Central retinal vein occlusion (CRVO) – high prevalence of systemic hypertension as much as 60% is reported in patients with CRVO. (Refer pg. 206)

4. Macroaneurysms – retinal macroaneurysms are seen in elderly with marked female preponderance and strong association exists with hypertension and arteriosclerotic vascular changes. Visual loss occurs secondary to macular edema, exudates, hemorrhage and retinal detachment.

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5. Anterior ischemic optic neuropathy – non-arteritic type typically occurs in elderly population with hypertension and diabetes.

Besides these hypertension might also cause- extraocular muscle palsy- carotid cavernous fistula

Pg 204Photocoagulation:

The principle behind laser treatment is to make hypoxic retina anoxic so as to reduce the stimulus for vascular endothelial growth factor (VEGF) production. ^ or diode

Pg 215S No FRESH RD OLD RD1. Convex configuration with opaque

or corrugated appearance due to intraretinal edema

Retinal thinning secondary to atrophy

2. Undulates freely with eye movements No movement seen3. Loss of underlying choroidal pattern.

Retinal blood vessels appear darkerPresence of demarcation line caused by RPE (retinal pigment epithelium) proliferation at junction of flat and detached retina

4. Presence of subretinal fluid Presence of intra retinal cysts if present over an year

5. May be associated with mild anterior uveitis

May be associated with faulty projection of rays, complicated cataract, hypotony, aqueous flare and neovascularization of iris.

Pg 216Management of primary retinal detachmentPrinciples include

1. Sealing the hole/ break2. Relieving vitreoretinal traction3. Drainage of subretinal fluidSealing retinal breaks

Retinal breaks need to be sealed to prevent further extension of retinal detachment. Closure of breaks stops further seepage of liquefied vitreous into the potential space between retinal pigment epithelium (RPE) and neurosensory retina.

This is achieved by1. Photocoagulation2. Cryotherapy 3. Scleral buckling procedure

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Photocoagulation and cryotherapy induces aseptic inflammation between RPE and neurosensory retina causing adhesion between the two layers. Photocoagulation (or) cryotherapy is applied in 2-3 rows at the margin of the break. Photocoagulation is done using diode or argon laser delivered by slit lamp (or) indirect ophthalmoscope.

The choice of using photocoagulation or cryotherapy depends on the location of the break.

Post equatorial lesions – photocoagulation Equatorial lesion – photocoagulation or cryotherapy Peripheral or anterior lesions – cryotherapy

Scleral BucklingScleral buckle creates an inward indentation of sclera and closes retinal breaks by

apposing the RPE to sensory retina by mechanical pressure. The inward indentation also releases vitreo-retinal traction. Scleral buckle may be an explant or implant and are made of hard or soft silicone. Types of buckle configuration are

1. Radial buckle – placed at right angles to limbus. Used for large horse shoe tears

2. Circumferential buckle – placed parallel to limbus. Used for multiple breaks located in one/two quadrants.

3. Encircling buckle – placed 360 degrees around the globe. Used for breaks involving three or more quadrants as in lattice/ snailtrack degeneration.

The buckle is sutured to the sclera and tightened so that the buckle produces the desired level of indentation.

Relieving vitreoretinal tractionIn cases of proliferative diabetic retinopathy or proliferative vitreoretinopathy.

2. Scleral buckle – by creating an inward indentation of sclera reduces the inner dimension of globe relieving vitreoretinal traction.

3. Three port pars plana vitrectomyAim

- To release anteroposterior and /or circumferential vitreoretinal traction- To clear the media

TechniqueThree sclerotomies are made 3-4mm from the limbus through the pars plana1st – infusion port – inferotemporal quadrant2nd – endoillumination port – superonasal quadrant3rd – primary active port – superotemporal quadrant

Vitreous bands, membranes, opacities and blood are removed by the vitreous cutter. Associated bleeding is controlled by endophotocoagulation. Retinopexy or sealing of holes is also done by endophotocoagulation.

Intravitreal substances are injected during surgery - to stabilize detached retina especially due to giant retinal tear - to counteract hypotony induced by fluid drainage- in macular hole surgery

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Commonly used substances are1. Air and sulphur hexafluoride mixture in the ratio of 70% and 30%2. Silicone oil3. Perflurocarbon liquids

Drainage of subretinal fluidIt is done to bring the break closer to RPE.

Indications1. Highly elevated bullous retinal detachment2. Long standing retinal detachment3. Inferior tears

Pg 217

S No Features Rhegmatogenous Exudative Tractional1. Pathogenesis Liquified vitreous with

Retinal breakAccumulation of subretinal fluid secondary to diseases of RPE (retinal pigment epithelium) or choroid

Tractional forces in vitreous/ retinal surface

SYMPTOMS2. Photopsia Present Absent Absent3. Floaters Present May be present

(if assoc. with vitritis)

Absent

4. Field defect Late peripheral defect. Involves central vision very late

Develops suddenly and progresses rapidly

Progresses slowly and remains stationary

SIGNS5. Shape Convex Convex Concave6. Elevation Moderate Bullous Shallow 7. Breaks Present Absent Absent8. Surface Corrugated Smooth Irregular9. Shifting

fluidPresent Present Absent

10. IOP Reduced Elevated Reduced

Pg 232Treatment of retinoblastoma

The modern trend in treatment is to postpone enucleation as long as possible and treat small and medium sized tumors with photocoagulation or cryotherapy and try to salvage the eye.

1. Quiescent stage and glaucomatous stage – small tumors can be treated by local modalities like cryotherapy, photocoagulation or brachytherapy with cobalt-60. Cryotherapy is employed in peripheral lesions with hazy media. Photocoagulation

15

is used in posterior lesion with clear media. Enucleation is still the most effective method of treatment of retinoblastoma. In this operation the importance of excising as long a portion of the optic nerve as possible cannot be over stressed. This is achieved by pulling on 2 traction sutures passed through the insertion of the 2 horizontal rectus muscles and then passing the enucleation scissors along the nasal wall of the orbit towards the optic foramen.

2. Stage of extraocular extension/ distant metastasis – a. Chemoreduction followed by local treatment or enucleation which reduces

the morbidity. Commonly used chemotherapy drugs are vincristine, etoposide and carboplatin.

b. The other alternative is to do exenteration of the orbit ie, removal of all the orbital contents including the periosteum.

Cryotherapy or photocoagulation is also indicated in cases where one eye has been enucleated and small tumour plaques are seen in the seeing eye.

Prognosis:Is poor. Death usually occurs due to intracranial extension.

Pg 235Treatment:1. Quiescent stage – small and medium sized tumors are treated with radioactive discs of gold or cobalt-60 or iodine-125. 2. Glaucomatous stage – radioactive discs (or) enucleation3. Stage of extraocular extension – exenteration of the orbit has to be done i.e. removal of all the contents of the orbit including the periosteum. 4. Stage of distant metastasis - Enucleation with local radiation to distant metastasis site.

When tumor is small and the affected eye is the only seeing eye, destruction by photocoagulation or suturing Cobalt disc to the sclera over the site of the tumour is indicated. Prognosis

Is poor: death usually occurs after some years.

Pg 240 & 242 *Systemic antibiotics

1. Intravenous Cloxacillin in combination with Gentamicin or Ceftazidime/Ceftrioxone is given. In case of infection with Methicillin Resistant Staphylococcus aureus, (MRSA) Vancomycin is preferred to cloxacillin.

2. Broad spectrum Fluoroquinolones, Ciprofloxacin 200mg IV BD.

Pg 249 Heriditary linked growth of retina is the determinant in the development of

myopia. The sclera due to its distensibility follows retinal growth but the choroids undergoes degeneration due to stretching which inturn causes degeneration of retina.

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Genetic factors

More growth of retina

Stretching of sclera

Increased axial length

Degeneration of choroids

Degeneration of retina

Degeneration of vitreous

Pg 254 * Strums Conoid

The configuration of light rays refracted through a toric surface is called Strum’s conoid. The more curved meridian will have greater refractive power and rays passing through this meridian will converge early than those falling on the less convex surface. The rays of light will hence have two foci and the distance between them is called the focal interval of Strum.

Cut section of light bundle passing through the toric surface is depicted in the figure. Fig

Description of Rays Cut sectionA Vertical rays converging more than

Horizontal raysHorizontal oval

B Vertical rays come to focus, Horizontal rays still converging

Horizontal line (first focus)

C Vertical rays are diverging, Horizontal rays still converging

Horizontal oval

D Vertical rays diverged as much as Horizontal rays have converged

Circle, called the circle of least diffusion

E Vertical rays diverging more than the convergence of Horizontal rays

Vertical oval

F Vertical rays diverging, Horizontal rays have come to focus

Vertical line

G Both Vertical and Horizontal rays are diverging

Vertical oval

The distance between the two foci B & F is called the focal interval of Strum.

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Pg OCULAR TRAUMA CLASSIFICATION GROUP

Mechanical Injury

Contusion injury

Penetrating injury

Perforating injury

Contusion – closed globe injuries occurring following blunt trauma are known as contusion or concussion injuries. Penetrating injury – full thickness outside to inside break in the ocular coats is known as penetrating injury.Perforating injury – when an object traverses the ocular coats twice having an entry and exit wound it is known as perforating injury. Globe rupture – blunt trauma causing inside to outside break in the ocular coats is known as rupture.

pg 273Treatment

- dislocated lens in anterior chamber is removed using wire vectis- posteriorly dislocated lens is removed through pars plana route by

impaling with MVR (microvitreoretinal) blade or floating with perfluorocarbon liquid.

Intraocular lens is placed over the iris or scleral fixated.

Pg 302 4) Cornea – specular microscopy for endothelial count.

Pg 30310) Ultrasonogram – B scan: to rule out posterior segment pathology

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Closed globe injury

Open Globe Injury

Globe Rupture Intraocular foreign body

Pg304S No Peribulbar Retrobulbar1 Site of injection Peripheral space or extraconal

spaceCentral space or intraconal space

2. Volume of injection 5 – 8 ml 1 – 2 ml3. Onset of action 10 – 15 min Immediate 4. Advantages - Additional facial block not

required- Complications are less

- Less volume of injection required- Immediate onset of action

5. Complications - Conjunctival chemosis- Raised orbital pressure(requires adequate ocular massage)- Subconjunctival hemorrhage

- Retrobulbar hemorrhage- Central retinal artery occlusion- Accidental sub-arachnoid injection

Broadly speaking there are 2 types of cataract extraction

Types of cataract surgery

1. Extracapsular cataract extraction (ECCE) A circular incision is made on anterior capsule with a cystitome. The nucleus and the

lens matter is removed leaving behind the rest of the capsular bag.Indications for ECCE

Other than dislocated lenses ECCE is now the surgery of choice for all senile and most cases of traumatic, developmental and complicated cataracts to enable insertion of a PCIOL.

2. Intracapsular cataract extraction (ICCE)The lens is removed with its capsule.

Indications for ICCEIn modern days, this is indicated only in grossly subluxated or dislocated lenses,

and when an anterior chamber IOL is planned.

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Extracapsular cataract extraction (ECCE) Intracapsular cataract extraction (ICCE)(Lens in-total, with intact anterior and posterior capsule is removed)

Conventional ECCE Manual small

incision cataract surgery or Manual phaco

Phacoemulsification

I Steps of conventional ECCE2. Pupils are well dilated before surgery for adequate exposure of lens using topical

medications like homatropine, tropicamide and cyclopentolate. 3. Surgery is done under surgical microscope4. Eyelids are retracted using Barraquer wire speculum which does not press on the

eyeball. 5. Superior rectus bridle suture is applied to turn the globe down and expose the

superior sclera for ease of surgery. 6. Peritomy to raise a fornix based conjunctival flap7. Bleeding vessels are cauterized using bipolar cautery. 8. Ab externo limbal incision is made at 12 o’clock limbus with Bard Parker knife

no. 15 by scratch incision. A 2mm long incision with entry into the anterior chamber is made.

9. Viscoelastic substance (hydroxypropyl methylcellulose) is injected into the anterior chamber to reform and maintain the anterior chamber.

10. Anterior capsulotomy is done using a cystitome (bent 26g needle)a. Can-Opener technique – multiple small radial cuts are made on the

anterior lens capsule 360 degrees at the edge of dilated pupil. These radial cuts are then joined by a circumferential cut made 360 degrees joining all the radial cuts. The central free flap is then removed.

b. Capsulorrhexis - a circular flap of anterior lens capsule is removed with cystitome (or) rhexis forceps.

N.B. Trypan blue dye can be used to stain the anterior lens capsule to aid in capsulotomy especially in mature and hypermature cataract where there is absence of red reflex.

11. The initial 2mm incision is now extended between 10 to 2 o’clock with corneoscleral scissors.

12. Hydrodissection is done to separate the cortical fibers from the lens capsule. It is done using a blunt tipped 26g angulated cannula. The cannula fitted to a 5ml syringe filled with Ringer lactate is introduced beneath the edge of anterior lens capsule left behind after capsulotomy and Ringer lactate is injected. The fluid wave cleaves a plane separating the cortical fibers from the capsule and from the nucleus. Completion of hydrodissection is indicated by being able to freely rotate the nucleus.

13. The nucleus is now delivered using lens expressor and spatula. With the spatula pressure is applied at the posterior lip of the section to open it widely, simultaneously the lower pole of nucleus is pressed with the lens expressor to lift the superior pole up out of the bag. Now with a forward motion of lens hook the nucleus is delivered through the section.

14. The cortical lens matter is then removed using Simcoe’s irrigation – aspiration cannula.

15. Viscoelastic substance is injected into the anterior chamber and capsular bag to facilitated intraocular lens (IOL) implantation. The IOL is grasped by the optic, the inferior haptic is inserted through the lips of limbal incision and then passed under the iris at 6o’clock. The superior haptic is then grasped with McPherson’s

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forceps and advanced into the anterior chamber and tucked under the iris at 12 o’clock.

16. Anterior chamber is washed with irrigating fluid to remove all viscoelastic substance.

17. The limbal wound is closed by 5 interrupted sutures with 8-0 or 10-0 nylon sutures.

18. Conjunctiva is cauterized over the section.19. Subconjunctival injection of dexamethasone and gentamicin is given. 20. Speculum is removed. 21. Eye patched with ciprofloxacin eye ointment.

II Steps of Manual Small Incision Cataract Surgery

1. Pupils are well dilated before surgery for adequate exposure of lens using topical medications like homatropine, tropicamide and cyclopentolate.

2. Surgery is done under surgical microscope3. Eyelids are retracted using Barraquer wire speculum which does not press on the

eyeball. 4. Superior rectus bridle suture is applied to turn the globe down and expose the

superior sclera for ease of surgery. 5. Peritomy to raise a fornix based conjunctival flap6. Bleeding vessels are cauterized using bipolar cautery7. A self sealing scleral tunnel incision is made with use of keratomes. An initial partial thickness scleral incision of 6-7mm length is made 2mm from limbus. Using a crescent blade (2.1mm keratome) scleral and corneal tunnel is made maintaining the initial depth of incision. The anterior chamber is entered using 3.2mm keratome (with its sharp tip). The keratome is placed in the previously created tunnel with the tip 1-2mm into the clear cornea. The tip is now angulated downwards to enter the anterior chamber. 8. Viscoelastic substance (hydroxypropyl methylcellulose) is injected into the anterior

chamber to reform and maintain the anterior chamber. 9. Anterior capsulotomy is done using a cystitome (bent 26g needle)

Can-Opener technique – multiple small radial cuts are made on the anterior lens capsule 360 degress at the edge of dilated pupil. These radial cuts are then joined by a circumferential cut made 360 degrees joining all the radial cuts. The central free flap is then removed.

Capsulorrhexis - a circular flap of anterior lens capsule is removed with cystitome (or) rhexis forceps. N.B. Trypan blue dye can be used to stain the anterior lens capsule to aid in capsulotomy especially in mature and hypermature cataract where there is absence of red reflex.

10. The initial incision is extended using 5.2mm keratome to 6-7mm tunnel incision.11. Hydrodissection is done to separate the cortical fibers from the lens capsule. It is done using a blunt tipped 26g angulated cannula. The cannula fitted to a 5ml syringe filled with Ringer lactate is introduced beneath the edge of anterior lens capsule left behind after capsulotomy and Ringer lactate is injected. The fluid wave cleaves a plane

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separating the cortical fibers from the capsule and from the nucleus. Completion of hydrodissection is indicated by being able to freely rotate the nucleus.12. The nucleus is first delivered out of the capsular bag onto the iris in the anterior chamber using dialer. One tip of nucleus is tipped out of the bag and the rest of it is rotated out of the capsular bag as a tyre is taken out of its rim. Now a wire vectis is placed between the prolapsed nucleus and iris surface and the dialer is placed between the nucleus and corneal endothelium. The nucleus is sandwiched between these two instruments and delivered out through the section. 13. The cortical lens matter is then removed using Simcoe’s irrigation – aspiration

cannula. 14. Viscoelastic substance is injected into the anterior chamber and capsular bag to

facilitated intraocular lens (IOL) implantation. The IOL is grasped by the optic, the inferior haptic is inserted through the lips of limbal incision and then passed under the iris at 6o’clock. The superior haptic is then grasped with McPherson’s forceps and advanced into the anterior chamber and tucked under the iris at 12 o’clock.

15. Anterior chamber is washed with irrigating fluid to remove all viscoelastic substance. 16. The incision has a self sealing architecture hence doesn’t require suturing. 17. Conjunctiva is cauterized over the section.18. Subconjunctival injection of dexamethasone and gentamicin is given. 19. Speculum is removed. 20. Eye patched with ciprofloxacin eye ointment.

III Phacoemulsification This procedure permits the removal of cataract through a self sealing small

incision (3-5mm), thus eliminating many of the complications of wound healing related to large insicions and significantly shortening of the recuperative period.

The unit consists of a hollow titanium needle which is activated by an ultrasonic mechanism to vibrate at 40,000 times a second in its longitudinal axis. This mechanical vibration transforms the lens matter into an emulsion which can be aspirated from the capsular bag and replaced by infusion fluid. An ordinary or foldable IOL can then be inserted into the posterior chamber through the same incision.

Phacoemulsification is more difficult to perform, especially on hard nuclear cataracts and though small pupils. It is contraindicated in patients with corneal endothelial dystrophy.

Differences between the different types of cataract extractionS No Conventional

ECCEManual Small Incision Cataract Surgery

Phacoemulsification

1 Incision 10 – 12mm 5 – 8mm 3 – 5mm2 Capsulotomy Can-opener/

CapsulorrhexisCan-opener/Capsulorrhexis

Capsulorrhexis

3 Nucleus delivery

Lens expressor & Spatula, pressure- counter pressure technique

Sandwich technique Emulsified and aspirated

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4 Sutures 5-7 interrupted sutures

Sutureless Sutureless

5 Post-op astigmatism

2-4 D 1-2 D 0.5-1 D

6 Post-op rehabilitation

6 weeks 3-4 weeks 1-2 weeks

7 Cost Cheap Cheap Costly

Pg 311Cataract extraction in diabetes mellitus:

The pre-operative management is the same as in the case of routine cataract. However certain points have to be stressed. 1. General examination

a. Diabetes to be controlledb. Associated hypertension to be treatedc. Septic foci such as carbuncle to be eliminated

2. Local examinationa. Septic focus such as stye to be treatedb. Slitlamp examination to rule out

i. Iridocyclitis – diabetes mellitus may be associated with iridocyclitis.ii. Rubeosis iridis – new vessels on iris

c. Retinal function should be assessed very well since there may be diabetic retinopathy. Importance of assessing diabetic retinopathy status

1. To explain post-operative visual prognosis2. Diabetic macular edema (CSME) and proliferative diabetic retinopathy worsens

rapidly following surgery due to the associated break in blood aqueous barrier (or) post-operative inflammation.

3. To prevent worsening, it is better to treat such eyes with laser before cataract surgery (or) at earliest following surgery.

4. Progression (or) worsening of retinopathy is also correlated with poor renal function and poor glycemic control, hence the importance of systemic control before surgery.

3. Cataract extraction a) It should be done under cover of antibiotics since diabetics are more prone

for infection. b) Poor mydriasis and pigment dispersion are common problems during surgery in diabetics.

c) Phacoemulsification is the procedure of choice as there is minimal breakdown of blood aqueous barrier (or) postoperative inflammation.

d) Posterior capsule barrier is important in diabetics to prevent rubeosis iridis hence care should be taken not to damage it.

e) Thorough removal of cortical fibers is necessary to reduce post operative inflammation and posterior capsular opacification (PCO)

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f) Capsulorrhexis with in-the-bag implantation of IOL also reduces risk of inflammation and posterior capsular opacification.

g) Acrylic IOL is preferred as it induces less inflammation and PCO formation.

(Note: Reduction of PCO formation is important for optimal fundus evaluation post operatively)

5. Postoperative complicationsa. More chance of infectionb. More chances of wound gapec. Increased incidence of postoperative iridocyclitisd. Visual prognosis depends on presence and stage of diabetic retinopathye. Progression of diabetic retinopathy following cataract surgery. f. Increased incidence of post operative cystoid macular edema

Pg 312Cataract extraction in cases of hypertension

The pre-operative management is the same as in a case of routine cataract. Certain points require stressing. 1. General examination

a) Hypertension to be controlled before surgeryb) Cardiac function assessment – ECG, ECHO to rule out associated ischemic

disease. In patients with poor cardiac function intraoperative ocular manipulations can initiate oculo-cardiac reflex and precipitate an ischemic event. In such patients cataract surgery is done under cardiac monitoring with help of anaesthetist. 2) Local examination – hypertension-associated posterior segment problems like hypertensive retinopathy, vascular occlusions, ischemic optic neuropathies are to be excluded prior to surgery for the purpose of visual prognosis after surgery. 3) Cataract extraction: The following complications are more likely to occur:

a. Bleeding during surgeryb. Vitreous upthrust and lossc. Hyphaemad. Expulsive hemorrhage due to associated sclerosis of choroidal vessels.

Pg 324* Based on the material used

i Rigid lens – made of polymethacrylateii Foldable lens - made of silicone, acrylic, HEMA (hydroxylethyl methacrylate)

Pg 341The causes of blindness in India are(National Survey on Blindness 2001-02)1. Cataract - 62.6%2. Refractive errors – 19.7%3. Glaucoma - 5.8 %4. Diabetic retinopathy – 4.7% 5. Surgical complications – 1.2%6. Corneal opacity - 0.9%7. Others - 5%

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Pg 343* Vision 2020

The “Right to Sight” is a global initiative launched by the WHO and a Task force of International non-governmental organizations to combat blindness. It was launched in 1999 in Geneva. Vision 2020 will serve as a common platform to facilitate a focused and co-ordinated functioning in eliminating avoidable blindness by 2020. Five conditions identified globally for immediate attention includes (WHO 1997)

1. Cataract 2. Trachoma3. Onchocerciasis4. Childhood blindness5. Refractive errors and low vision

Five basic strategies adopted to combat blindness are1. Disease prevention and control2. Training of personnel3. Strengthening existing eye care infrastructure4. Use of appropriate and affordable technology5. Mobilization of resources

Each country will decide on its priorities based on the magnitude of specific blinding conditions in that country.

The Right to Sight in India – Vision 2020Vision 2020 was included under NPCB (National Programme for Control of

Blindness) in 2001. The strategies framed include

1. Strengthening advocacy 2. Reduction of disease burden 3. Human resource development4. Eye care infrastructure development

1. Strengthening advocacyEssence of the activity is to create public awareness about eye care and blindness

prevention. Strengthens the existing function of DBCS (District Blindness Control Society) and involve NGO’s, community societies and leaders. 2. Reduction of disease burden

The diseases identified in India under vision 2020 includesI. Cataract (62.6%) – commonest cause of blindness in people above 50

years of age according to National Survey of Blindness 2001-02. II Childhood blindness – common causes are vitamin A deficiency, measles,

ophthalmia neonatorum, congenital cataract, retinopathy of prematurity. Refractive error is the commonest cause of visual impairment in children (19.7% - National Survey on Blindness 2001-02). Childhood blindness has achieved greater significance due to the increase in number of disability years.

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III Glaucoma – stands as a cause blindness in 5.8% of people aged above 50 years. Opportunistic screening and training existing health care workers helps in detecting this condition.

IV Diabetic retinopathy – 4.7% of people above 50 years of age are blind due to diabetic retinopathy.

V Corneal blindness (0.9%) – important causes are keratomalacia, trachoma, ocular injuries and corneal ulcer. Prevention of xerophthalmia and trachoma will help to reduce the number of corneal blindness. 3. Human resource development

Mid level Ophthalmic Personnel are introduced to work at both hospital and community level. They include ophthalmic nurses, ophthalmic technicians, optometrists and orthoptists. 4. Eye care infrastructure development

According to WHO recommendations we need to develop:1. Primary level vision centres – 20,000 vision centres each covering a population of

50,000.2. 2000 Service centres at secondary level covering population of 5 lakhs. 3. Training centres – tertiary level. 200 such centres for a population of 5 million4. Centre of Excellence catering to a population of 50millions. 20 such COE’s need

to be developed.

Figure Bard Parker handle & no 15 blade

Used to make incisional groove in cataract surgery and trabeculectomy. Make skin incision in various extraocular surgeries.Fine Canula

Used to do hydrodissectionHelps to form and wash the anterior chamber

Crescent blade Makes the tunnel incision in small incision cataract surgery

3.2mm KeratomeUsed to enter the anterior chamber after tunneling in small incision

cataract surgery and phacoemulsification5.8mm Keratome

Used to enlarge the section in small incision cataract surgery and phacoemulsification

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1) Diabetic retinopathy:Introduction: The occurrence of retinopathy in a diabetic depends on the duration of the disease and not on the chronological age of the individual i.e. it is said to be more common after the disease has lasted for about 10 years. The insulin-dependent types are more prone for the development of proliferative retinopathy whereas the non-insulin dependent types are more prone for the development of diabetic maculopathy. Other risk factors include poor metabolic control, hypertension, nephropathy, anaemia, smoking, hyperlipidemia, pregnancy, obesity.

Pathology: Microangiopathy affecting the retinal capillary bed is the pathology in diabetic retinopathy. Capillary changes consist of:

- loss of pericytes- thickening of basement membrane- proliferation of endothelial cells

Histological changes include- deformation and increased rouleaux formation of red blood cells- increased platelet stickiness and aggregation leading to decreased transport

of oxygen.

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