Retinal Disease Alters Size Perception: a Case Report

Aniseikonia is a difference in the perceived size of an object seen by each eye. It most commonly occurs when the two eyes have different refractive errors (anisometropia). The difference in perceived size makes it difficult for the patient to combine the images into single binocular image perceived by both eyes. However, few tests are available to quantify aniseikonia, and it can be overlooked as a primary symptom and impediment to binocular vision. In addition to anisometropia, aniseikonia can be retinally induced in anisometropia and from retinal disease which creates a difference in the number of retinal cones processing the image in each eye causing perceived size differences between eyes. A 31-year-old healthy white male complained of a significant difference between the size of the image seen by each eye, most notable during computer work. The patient had bilateral central serous chorioretinopathy (focal detachments of the retina) which were treated successfully by a retinal specialist during the previous 2 years. Yet significant aniseikonia persisted despite resolution of the focal detachments. Correction with spectacle lenses which neutralized the perceived size difference between eyes significantly decreased the patient’s symptoms. Aniseikonia is a significant impediment to binocular vision which can be rectified with proper optical correction. This atypical case exemplifies its impact of retinal rather than optical differences between eyes. Awareness of aniseikonic symptoms, etiology, measurement techniques, and optical correction are needed to optimally use both eyes together as a team.