Aniseikonia is the difference in image size perceived between the eyes from unequal magnification. The two most common causes are anisometropia and retinal pathology. Symptoms of aniseikonia include diplopia, headache, dizziness, disorientation, and excessive eye strain.
Aniseikonia is the difference in image size perceived between the eyes from unequal magnification. When the magnification variance between the two eyes is disproportionately high, symptoms can arise.
Aniseikonia typically occurs due to either anisometropia or macular pathology. Up to 7% of aniseikonia between the eyes is usually tolerated.
- Anisometropia Aniseikonia: When there is greater than 3D of anisometropia, aniseikonia can occur. This may occur naturally due to antimetropia (one eye hyperopic and the other myopic), aphakia, or simple anisometropia.
- Retinal Aniseikonia: Macular pathology such as cystoid macular edema, macular pucker, epiretinal membrane, macular schisis, central serous chorioretionopathy, macular holes, and other anatomical abnormalities can lead to compression, stretching, or damage to the retina. This will cause light projected on the retina by a perceived image to appear larger (macropsia) or smaller (micropsia), as a variable number of photoreceptors may be stimulated.
Aniseikonia can induce diplopia, headaches, dizziness, disorientation, eye strain, suppression, and balance disorders. The diplopia caused by aniseikonia is not relieved with prisms therapy.
Treatment varies based on the cause of aniseikonia. When it is due to anisometropia, treatment is with glasses, contact lenses, corneal refractive surgery, or lens-based refractive surgery. When due to retinal pathology, magnification size-matched lenses known as isokonic lenses can be used.
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