Aniseikonia due to large amounts of astigmatism is best corrected by which method?

• A. Spectacles
• B. Contact Lenses
• C. Laser Surgery
• D. Intraocular Lenses

Answer: (B)

Aniseikonia happens when each eye produces an image that is a different size. With large astigmatism, correcting with eyeglasses often changes the magnification differently in each eye because of vertex distance and the way cylindrical power is applied in spectacles. This can make the size difference between the two images even more noticeable. Placing the correction on the eye with a contact lens places the corrective power directly on the cornea, reducing those magnification differences between eyes. Toric contact lenses can precisely correct astigmatism and align magnifications, so the two eyes see more similar image sizes. Laser surgery and intraocular lenses change the refractive error but don’t address the image-size disparity caused by differing magnifications between the eyes, so they’re less effective for reducing aniseikonia in this scenario.