Aniseikonia Induced by Cataract Surgery and Its Effect on Binocular Vision

Purpose. This study measured aniseikonia before and after the first and second cataract surgeries in ametropic adults. The relationship of aniseikonia to anisometropia and its effect on stereopsis, ocular alignment, and clinical symptoms were determined. Methods. Seventeen patients scheduled to have bilateral cataract surgery with 2 diopters or more ametropia participated. Patients were evaluated before cataract surgery and 4 weeks (+/- 1 week) after the first and second surgery. Visual acuity, refractive error, aniseikonia, stereopsis, ocular alignment, and visual symptoms were determined at each visit. Results. Aniseikonia increased after the first cataract surgery. The increase in aniseikonia occurred in concert with increased anisometropia and resulted in poorer stereopsis overall. Aniseikonia and anisometropia 1 month (+/- 1 week) after the second cataract surgery returned to near baseline and were associated with better stereopsis. The amount of aniseikonia showed substantial variance and could not be predicted by the amount of induced anisometropia. Changes in ocular alignment were minimal. Statistically significant changes in patient symptoms between study visits were infrequent. Conclusions. Aniseikonia induced by cataract surgery may not be a substantial problem for ametropic adults with normal binocular vision, at least in the short term.