Unilateral Aphakia and Contact Lenses*

The size of the retinal image in the corrected aphakic eye is some 24% larger than the image before removal of the crystalline Len's. This large differential makes binocular vision impossible in individuals with unilateral aphakia corrected by spectacle lenses. A similar calculation, but with a contact lens correction, reduces this figure to about 8% (Dawson, 1962) . Theoretically, intraocular lenses represent a nearly ideal approach to correcting unilateral aphakia. However, in practice the procedure is fraught with so many long-term complications that today this approach has all but been abandoned as a feasible way of achieving binocularity in unilateral aphakia (Lieb and Guerry, 1957; Guerry and Geeraets, 1962). I agree with Welsh (1961) that, for the patient with unilateral aphakia, a contact lens affords the only reasonably safe method of correcting the aphakic refractive error to allow a balanced normal or near normal type of binocular vision unattainable with a cataract spectacle lens. A search of the literature of the last ten years, however, fails to uncover sufficient data about the type and degree of binocularity obtained by contact lens correction of