Helping the aphakic neonate to see

The treatment of the infant who is born with sensory deprivation amblyopia is one of the most difficult therapeutic problem sets facing the ophthalmologist today. This group of anomalies has many forms, the most common of which seems to be unilateral and bilateral cataracts. Substantial advances have been made, however, in many aspects of therapy for infants who have this set of problems. We have come to realize that it is essential to address these conditions at the first moment that is consistent with the safety of the child. New techniques in cataract extraction have reduced the time course of surgical treatment, reduced the frequency of secondary cataracts, and sustained the patency of the visual pathway. Unfortunately, practitioners who engage in the surgery may not have the back-up skills in advanced contact lens fitting, correction of aniseikonia, and, in some instances, the strabismological complications which are encountered. Further, improved means of assessment of visual acuity, binocular vision, and other visual characteristics of these infants are only in the developmental stages at this time. Thus, we propose to present the problem in an orderly manner. We shall first review the types of cases and problems. We will then discuss surgical techniques and the information which must be determined during examination under anesthesia (EUA) for the purposes of visual correction. We will then describe the designs of the spectacle lens and/or spectacle/contact lens combinations that are used to correct the resultant aniseikonia and anisometropia. We will address the approaches to patching and techniques on how to best achieve binocular vision in these patients. Separately, means and methods of assessment of vision by preferential looking, visual evoked response, optokinetic nystagmus, and tests of other visual functions will be explored. In summary, we will try to tie together the entire therapeutic regimen that can be used in the treatment of these patients.