What solution is best depends on the amount of aniseikonia, type of aniseikonia ( optical-induced or retinally-induced ), the refraction, and the importance of cosmetics.
Aniseikonia can occur naturally or be induced by the correction of a refractive error, usually anisometropia ( having significantly different refractive errors between each eye ) or antimetropia ( being glasses and contacts.
For most of his life Williams suffered from eyestrain caused by aniseikonia, a condition that was not recognized during his youth; he had glasses specially made to treat the condition in the 40s.
The distortions can make objects look different in size ( usually larger = macropsia ), especially in the central portion of the visual field, creating a localized or field dependent aniseikonia that cannot be fully corrected optically with glasses.
Research at the institute concentrated on binocular vision, including cyclophoria ( the tendency of the eyes to rotate in opposite directions in their sockets ) and aniseikonia ( in which each eye has a differently sized retinal image of the same object ).