[Intra-ocular optics and contact lens correction in unilateral aphakia]

After an explanation of intra-ocular optics, the first results of combined contact lens correction in 42 patients are reported. As opposed to the conventional type of contact lens treatment in monolateral aphakia, this method has four main advantages: 1. It enables practically identical sight in both eyes, thus providing the necessary conditions for binocular vision both at a distance and close-up. 2. The recovery of sensomotor haptics in both eyes prevents squinting, even in the case of incipient cataract of the other eye. 3. Premature lens extraction in the second eye can be postponed and delay in lens extraction in the first affected eye can be avoided. 4. In cases where dioptric aniseikonia is very marked, as in myopia, a bilateral spectacle-contact lens combination enables tolerable binocular vision to be achieved even without an aniseikonic lens. Our findings indicate that the conventional contact-lens correction of monolateral aphakia is never satisfactory in cases with a moderate to high degree of myopia and in all refraction defects in young patients. Echometry, objective measurement of aniseikonia and combined contact lens correction helps most of these patients to regain binocular vision, both close-up and at a distance. In practice, rules of thumb and principles can be established. Even without the aid of echometry and objective aniseikonic measurement, Rule 1 enables us to prescribe combined contact lens correction for 80% of all presbyopic patients, thus enabling them to regain comfortable binocular vision. We all know that monolateral aphakia is, unfortunately, no triumph of ophthalmological science, but rather a serious eye defect that we must correct as best we can. Conventional contact lens correction, delay in operation for cataract of the first affected eye, as well as premature operation of the second eye are, in many cases, of as little help to our patients as monolateral cataract spectacles, with occlusion of the healthy eye with normal or dark glass. In contrast, combined contact lens correction in many cases of monolateral aphakia enables the patient to regain binocular vision.