Management of adult cataract II.ppt

Management of Adult Cataract

Prof. Naimatullah Khan Kundi

Head, Department of Ophthalmology

Khyber Teaching Hospital

Peshawar

Cataract Surgery

Types:

1. ICCE

1. ECCE

Standard (Manual Nuclear Expression)

Phacoemulsification (Ultrasonic Nuclear

Fragmentation)

Management of Adult Cataract

Cataract Surgery

Intra Capsular Cataract Extraction (ICCE)

Definition:

Removal of cataractous lens in its entirety

from the eye

Complete removal of the lens and its capsule

Cataract Surgery

Extra Capsular Cataract Extraction (ECCE)

Definition:

ECCE involves removal of the nucleus and cortex

through an opening in the anterior capsule,

leaving the posterior capsule in place

Cataract Surgery

ICCE

ICCE evolved into a very successful operation

Preferred surgical technique before the refinement

of modern ECCE surgery

However there remained 5% rate of potentially

blinding complications including:

Infection

Hemorrhage

RD

CME

Cataract Surgery

ECCE has replaced ICCE, almost entirely in most parts

of the world:

1. Better operating microscopes

2. More sophisticated surgical aspiration systems

3. More sophisticated IOL implants

Pre-operative evaluation and information

General health

Drug History

Ocular and social histories

Ocular examination

Measurement of visual function

Preoperative measurement


General health

A complete medical history starting point

Ophthalmic surgeon should work with patient’s

primary care physician to achieve optimal

management of all medical problems like:

DM

IHD

COPD

Bleeding Disorders

Adrenal Suppression by Corticosteroids


Awareness of any Drug sensitivities and

medications:

Immunosuppressants

Anticoagulants:

These may alter the outcome of surgery


Ocular history

Helps ophthalmologist identify conditions that could affect: Surgical Approach Visual Prognosis

Hx of: Trauma

Inflammation

Amblyopia can affect visual prognosis

Glaucoma

Optic nerve

Retinal disease

Past record may show patient’s visual acuity prior to development of cataract


Ocular history (cont’d)

Information about the postoperative course in

fellow eye

Any problem in the first operation:

IOP Vitreous loss CME Endophthalmitis Hemorrhage

The surgical approach & post operative follow-up can be

modified for the 2nd operation to risk of similar

complications


Social History

Important for documenting patient’s subjective

visual disability

Surgeons should be aware of patient’s occupation

and life style

External examination (pre-op Evaluation)

Body habits:

Bull Neck, Kyphosis, Obesity, Head Tremor

These have effect on surgical approach

Enophthalmos, prominent brow

Entropion, Ectropion & other lid abnormalities noted

and treated

Blepharitis: Diagnosed and treated

Abnormal tear dynamics, exposure keratitis corneal

sensation noted


Motility:

Ocular alignment evaluated

EOM tested for their range of movements

Cover testing (muscle balance):

Any abnormality might suggest pre-existing strabismus

with amblyopia as cause of visual loss

Tropia: may result in diplopia following surgery


Pupil

Pupillary responses to light and accommodation

evaluated

Direct & consensual constriction of pupil

Swinging-flashlight Test:

To detect RAPD (Indicative of serious

retinal / optic nerve dysfunction)


Biomicroscopic examination

Conjunctiva

Scarring / lack of mobility over sclera

Symblepharon / shortening of fornices

(underlying systemic/ocular surface disease):

Can limit surgical approach

Loss of vascularization (Previous chemical

injury / scarring from ocular surgery):

Change in surgical approach



Conrnea

Corneal thickness, presence of Guttata and

marked abnormalities of endothelium

Specular reflection and SL examination provide

estimate of endothelial cell count and

morphology



Conrnea (cont’d)

Thickness> 600 µm suggest poor prognosis

for corneal clarity following cataract surgery.

Surgery tailored to minimize trauma to corneal

endothelium

Cornea inspected for corneal arcus / stromal

opacities (may limit view during surgery)


Biomicroscopic examination Anterior Chamber

Shallow AC: Intumescent lens

Forward displacement by posterior pathology (e.g. CB Tumor)

AC depth observation and lens nucleus size:

Help surgeon plan and choose between expression / phacoemulsification

Preoperative gonioscopy (esp. when AC-IOL is anticipated)

PAS Neovascularization Prominent major arterial circle



Iris Pupil size after dilation noted (important for

planning surgical technique)

Presence of PS noted

Poor pupillary dilation: the following measures may provide adequate exposure

1. Radial iridotomy

2. Sector iridectomy

3. Posterior synechiolysis

4. Sphincterotomy

5. Iris retraction



Lens

Lens appearance noted before and after dilation of pupil

Visual significance of “oil droplet” nuclear cataracts and

small PSCs best appreciated before dilation of pupil

Exfoliation syndrome best seen following dilation

Nuclear size and brunescence evaluated for

phacoemulcification (after dilation)



Lens (cont’d)

Medial clarity in visual axis evaluated to

assess lenticular contribution to the visual

deficit

Posterior capsule focused with thin SL beam,

the light then changed to cobalt blue and if PC

no longer illuminated, the media is 20/50 or

worse (blue light scatter)



Lens (cont’d)

PSC (small) may cause severe visual loss:

Conversely dense brunescent nuclear sclerotic

cataracts may allow surprisingly good visual

acuity



Lens (cont’d)

Lens position and zonular fibers integrity also

evaluated

Lens decentration

Excessive distance between lens and

pupillary margin (may indicate

subluxation)

Indentation/flattening of lens periphery

might indicate focal loss of zonular support

Fundus Evaluation

Ophthalmoscopy (Direct & Indirect)

1. Anatomical integrity of posterior segment assessed

2. Media clarity (direct opthalmoscope)

3. Macular, ON, Retinal vessels, Retinal periphery

evaluated

4. ARM may limit visual rehabilitation after otherwise

uneventful cataract ext.

Fundus Evaluation

Ophthalmoscopy (Direct & Indirect) (cont’d)

5. Diabetic patients examined carefully for:

Macular edema

Retinal ischaemia

Neovascularization

Retinal ischaemia may progress to posterior or

anterior neovascularization in case of

ICCE or

ECCE (with PC rupture)

Fundus Evaluation

Ophthalmoscopy (Direct & Indirect) (cont’d)

6. Peripheral retinal examination may reveal:

Vitreo-retinal traction

Lattice degeneration

Preexisting retinal holes

ICCE & Primary decision of PC are associated with

incidence of RD and CME

Which may warrant preoperative treatment

Optic Nerve

Examined for color, CD ratio or any other

abnormality

ON functions further evaluated by:

VA

Confrontation VF testing

Pupillary Examination

Other Methods

Mature cataract prevents direct visualization of

posterior segment

B-Scan ultrasonography

RD

Posterior segment tumor

Light projection

Maddox Rod projection

Helpful in detecting

retinal pathology

Measurements of visual function

1. VA Testing

2. Brightness Acuity

3. Contrast Sensitivity

4. Visual Field Testing


1. VA Testing

Test both near and distant visual acuity

Refraction to determine BCVA

PH VA

VA can improve after pupillary dilation (esp. in PSC)


2. Brightness Acuity

Test near and distance visual acuity in well lighted

room of patient with complaint of glare

Under these conditions, patient with cataract shows

3 or more lines compared with VA in the dark

Variety of instruments available to standardize and

facilitate this measurement


3. Contrast Sensitivity

Patients with cataracts may experience contrast

sensitivity even when Snellen acuity is preserved

Variety of instruments and charts available to test

in clinical setting


4. Visual Field Testing (VFT)

VFT may help to identify visual loss from other disease process:

Glaucoma

ON disease

Retinal abnormalities

Confrontation VFs should be tested

Goldmann or automated VF testing helps to document degree of preoperative visual loss

Light projection helpful to test peripheral VF in patients with dense cataracts


5. Special Tests

1. Potential acuity estimation

Helpful in assessing the lenticular contribution to

visual loss

Methods:

Laser interferometry

Potential acuity meter


5. Special Tests

1. Potential acuity estimation (cont’d)

Laser interferometer:

Twin sources of monochromic helium-neon laser

light creates a diffraction fringe pattern on the

retinal surface

Transmission of this pattern mostly independent

of lens opacities

Retinal VA estimated by varying the spacing of

the fringe


5. Special Tests


Laser interferometer (cont’d)

The area of pattern subtending the retina is considerably

larger than fovea

Thus small foveal lesions that limit VA may not be

detected

Potential acuity meter: Projects a numerical or snellen

vision chart through a small entrance pupil

Image can be projected into the eye around lenticular

opacities


5. Special Tests


Potential acuity meter

Projects a numerical or Snellen vision chart through a

small entrance pupil

Image can be projected into the eye around lenticular

opacities


5. Special Tests

1. Potential acuity estimation (cont’d)

Laser interfermeter & potential acuity meterdeterminations useful in estimating VA before surgery

Both much predictive in moderate lens opacities

Misleading In:

ARM

Amblyopia

Glaucoma

Serous Retinal Detachment

Small macular scar

Macular edema

Accurate clinical examination of the eye is as good a predictor of the visual outcome as these tests


Cataracts obstruct fundus view

Direct examination may be difficult

1. Maddox Rod

2. Photo-Stress Recovery Test

3. Blue-light entoptoscopy

4. Purkinje’s entoptic phenomenon

5. Electro-retino-graphy (ERG)

These tests measure

function rather than

appearance


1. Maddox Rod

Red line viewed by the patient (orientation)

Grossly evaluates macular function

Large scotoma appears as loss of red line as

viewed by the patient


2. Photo-stress recovery test

Photo stress recovery time used to semiquantitavely judge

macular function

Penlight shown into a normal eye (photo stress) and

recovery period noted

This period is necessary before the patient can identify the

Snellen letters one line larger than that individual’s baseline

VA (photo stress recovery time)

Normal average time: 27 sec. With std. Deviation of 11 sec.

In most cases this time is 50 sec. Or less

Prolonged time is an indication of macular disease


3. Blue-light entoptoscopy

Patient is asked to view intense, homogenous

blue-light background

White blood cells produce shadows as they course

through perifoveal capillaries

If the patient sees these shadows, macular

function is probably intact

Many patients find the test difficult to comprehend,

which limits its usefulness


4. Purkingje’s Entoptic Phenomenon

Subjective test

Rapidly oscillating point source of light is shown

through closed eye lids

Ability of the patient to detect shadow images of

his/her retinal vasculature provides a very rough

indication that retina is attached


5. Electro-retino-Graphy (ERG) & Visual Evoked

Response (VER)

In rare cases these tests can be done to

evaluate retinal and or ON function

where other testing is inconclusive

Health & Medicine

Management of adult cataract II.ppt