I have been treating many patients with Aniseikonia over the past 10 years. Some even come from out-of-state for the Aniseikonia Evaluation since there are very few optometrists who provide such evaluation and treatment these days. The following are the FAQ list:
• What causes aniseikonia?
Aniseikonia can be caused by any asymmetric changes in the optical components of the eyes that results in a difference in retinal image size. Possible causes may include unequal prescription between the two eyes, cataract surgery, intraocular lens implant, refractive surgery, retinal detachment, and macular degeneration.
• How come I haven’t heard of it before?
Aniseikonia is very difficult to diagnose. Many of the classical instruments that measure aniseikonia are not manufactured any more. Only a few eye clinics today are equipped with the expertise and instrumentation to diagnose and treat aniseikonia.
• How common is aniseikonia?
As many of 10-15% of the population may have some aniseikonia; not everyone becomes symptomatic from it. It becomes clinically significant (about 4% of the population based on the Dartsmouth Study) usually if (1) it is of late-onset, i.e. the brain has a hard time readjusting to the size difference, (2) the patient is very sensitive to small visual changes, and/or (3) the patient’s work of life-style places great demand on the visual system.
• Can aniseikonia be measured?
Yes. At our clinic, we utilized a state-of-the-art aniseikonia test that measures aniseikonia to the nearest 1%.
• What are iseikonic lenses (size lenses)?
Iseikonic lenses are custom-designed lenses that alter the magnification in one or both eyes by changing several lens parameters: front curvature, center thickness, vertex distance, and/or lens material. The perceptual disturbances caused by the image size difference between the two eyes are relieved by either magnification of the eye seeing through the smaller image and/or minification of the eye seeing through the larger image.
• Can anything be done about it?
Yes. Iseikonic lenses, contact lenses, vision therapy, occlusion therapy, or a combination are possible treatment options . Only a comprehensive evaluation can confirm the diagnosis of aniseikonia and rule out other similar visual disorders before the best recommendations can be made.