Management of developmental cataract

Work up

History - Rash/ febrile illness/ drug use/ X ray

exposure during pregnancy- Any systemic diseases in the child- Family history

Examination- Assessment of visual acuity:< 3yrs: Look for :CSMF (central steady maintaining fixation)Resistance to closure of one eye

3-6 yrs: Illiterate E chartLandolt C test

>6 yrs: Snellen’s chart

- Strabismus -} indicate amblyopia and - Nystagmus -} guarded visual prognosis - Pupillary reactions- Associated ocular abnormalities:

microcornea/ aniridia/ glaucoma/ microphthalmos/ PHPV/ retinitis pigmentosa

- Fundus examination- Retinoscopy

Systemic examination:- To r/o systemic diseases- To r/o any systemic infections which may be a

contraindication to surgery Investigations:- Ocular investigations: A-scan and keratometry: for IOL power

calculation B-scan: if fundus examination is precluded by

the cataract

Lab investigations:

Blood: - Glucose- TORCH titres- Calcium

Urine:- Reducing substances: galactokinase def.- Nitroprusside test: homocystinuria

Factors influencing management Visual significance:Depends on :- Morphology of cataract: nuclear cataract> zonular

cataract- Density, size and location: larger (>3mm), denser and

more central and posterior cataracts cause greater visual handicap

- Presence of squint and nystagmus: indicate amblyopia and hence significant cataract

Laterality:- Unilateral cataract needs to be operated upon

immediately to prevent amblyopia- Bilateral cataracts should be operated upon within 2

months (critical period) before fixation develops to prevent amblyopia. The eye with the denser cataract should be operated first followed soon (within 5-10 days) by the other eye

Treatment

Visually insignificant small non axial opacities can be safely ignored

Occlusion therapy to treat amblyopia if vision is worse than that can be accounted for by the cataract

Dilatation with 2.5% phenylepherine in patients with small axial opacities

Optical iridectomy in patients requiring chronic dilatation

Surgical:

Lens aspiration with/without IOL implantation

The decision to implant IOL is based upon:- Age of child: Since child’s eye is a growing eye,

primary IOL implantation is not preferred in children <2 yrs of age with bilateral cataract to avoid errors in IOL power calculation

- Laterality: Unilateral cataract should always treated by primary IOL implantation because unilateral aphakia in children is difficult to treat

- Primary posterior capsulotomy (PPC) should be performed in all children < 2 yrs to prevent PCO formation which has an incidence of ~100% in children < 2 yrs

- Limited anterior vitrectomy should also be performed an these cases along with PPC because the anterior vitreous may act a scaffold for the lens epithelial cells to grow

IOL power calculation in children

Since a child’s eye is a growing eye, the IOL power calculation in children may result in refractive changes (myopic shift) after complete growth of eyeball. Hence adjustments need to be made in calculations of IOL power in children to avoid refractive errors later.

< 2 yrs: 80% of calculated IOL power 2-8 yrs: 90% of calculated IOL power > 8 yrs: full correction

Difficulties in surgery for pediatric cataract

Intraoperative: - AC shallowing: high viscosity VES

needed to keep AC formed- Difficulty in performing CCC: due to

more elastic capsule in children- Cortex removal may be difficult due to

finer lens fibres

Postoperative:- PCO: 100% risk- Inflammation is more- Risk of formation of synechiae- IOL decentration more common

Postoperative correction of aphakia Bilateral aphakia: - Spectacles: convenient, inexpensive mode of

treatment- Contact lenses: less image magnification

Power of spectacles and contact lenses is calculated by retinoscopy and a near vision add of +3 D to be given in all children < 1 yr as the field of interest for an infant is near.

- Secondary IOL implantation: after the age of 2 yrs when eyeball growth is complete, IOL can be implanted

Unilateral aphakia:- Ideally primary IOL implantation should be done

in all cases with unilateral cataract irrespective of age to avoid problems in correction of unilateral aphakia

- Contact lenses are chosen over spectacles due to lesser image magnification

- Secondary IOL implantation as soon as possible