What is Aniseikonia?

Aniseikonia is a vision problem where information about the size of objects in the visual field varies between eyes or along a plane of vision. People may also notice variations in shape. A simple test can be used to check for aniseikonia in patients, by showing patients an image and having them view it through both eyes and each eye separately to see if there are distortions in the size or shape between the eyes. This condition is treatable with corrective lenses.

Some people naturally have aniseikonia as a result of having radically different visual acuity in both eyes, or because of variations in the size and shape of the eyes themselves. In other cases, the condition may be induced by corrective lenses, especially when patients have different prescriptions and they are complex. The variation may be subtle, but it can cause problems for the patient because the difference in the visual field can cause a cascading series of visual errors.

People with aniseikonia often develop eye strain, dizziness, disorientation, and balance problems. They can have trouble with depth perception and manipulating objects in their environment. They may also have difficulty processing visual scenes, something that can be potentially hazardous while engaging in activities like driving or operating heavy machinery. When the difference in image size is very small, people may not realize what is going on until they are evaluated by a doctor.

Treatment for aniseikonia usually involves corrective lenses ground to address the problem and stabilize image size. For people with an existing prescription to correct refractive errors, these lenses need to be specially made to address the underlying vision problem and the aniseikonia. Surgical treatments are not yet available, but sometimes receiving surgery to correct refractive errors or replace the lens of the eye with an artificial lens can make it easier to treat the aniseikonia.

Diagnosis of this condition usually requires a workup by an ophthalmologist. The doctor will examine the eyes, run a series of vision tests to learn more about the patient's visual acuity, and interview the patient about any vision or health problems noted. This information can be pulled together to develop a diagnosis, determine how severe the problem is, and work on a treatment plan. Patients may benefit from visiting an aniseikonia clinic, where they get specialized care from vision professionals who focus on this condition and have access to the latest diagnostic equipment and treatment options.