Outcome after surgery of congenital cataract

Abstract

The visual outcome in infants undergoing surgery for bilateral congenital cataract has improved considerably because of improved surgical methods and the realisation that early detection, allowing early cataract extraction and immediate optical correction, can prevent otherwise irreversible deprivation amblyopia.

The management of unilateral congenital cataract is still of the most difficult problems in paediatric ophtalmology. In unilateral congenital cataract, intervention before six weeks of age has been reported to be optimal to promote visual acuity development. However, in spite of early surgery the results in unilateral cataract have in general been less favourable due to the interocular competition.

Cataract surgery in adults is a safe procedure but complications are more common in children. The aims of the projects were to account for complications and long-term functional results after surgical treatment of children with dense congenital unilateral and dense bilateral congenital cataract operated on before 12 months of age. Intraocular lens (IOL) implantation in infants might be P, better alternative to aphakia. One aim was to study, in an animal model, the effects of IOLs specially designed for the small growing eye.

Complications requiring additional surgery were very common in these infants operated on for congenital cataracts during the first year of life. After-cataract occurred in more than one third of the eyes. Glaucoma requiring trabeculectomy developed particularly in infants who had their cataract extraction very early. Glaucoma development was not more common in infants operated on for after-cataract. The visual outcome was not worse in eyes operated on for after-cataract.

In dense bilateral congenital cataract good postoperative visual acuity was achieved in most healthy children if surgery was performed early, i.e. before 6-8 weeks of age. Chronic glaucoma developed predominantly when the cataract extraction was performed during the first week of life. In dense unilateral cataract a good visual acuity was achieved only in children who underwent cataract surgery early and who adhered to the occlusion therapy schedule. Full compliance to the occlusion therapy was uncommon. Chronic secondary glaucoma leading to blindness developed in three out of 12 children operated on within 6 weeks. Persistent foetal vasculature seemed to be a risk factor for secondary glaucoma.

The effects of two types of IOLs designed for small eyes with long haptics forming a ring in the capsular bag were investigated in infant rabbit models and compared to conventional 3piece AcrySof® IOL and aphakia. The 3-piece AcrySof® IOL was strongly deformed in these small eyes and the vaulting of the lens caused occlusion of the pupil. This lens should probably be avoided in very small eyes. The specially designed IOLs for small eyes did not dislocate but the bulb growth was compromized. The IOLs reduced or prevented the formation of after-cataract. Considerable after-cataract developed in all aphakic eyes. Glaucoma occurred in pseudophakic eyes as well as in aphakic eyes.