A general rule states that for every 1.00 D power difference between the two eyes, there will be approximately _____________% aniseikonia.

A general rule states that for every 1.00 D power difference between the two eyes, there will be approximately _____________% aniseikonia.

• A. 0%
• B. 1%
• C. 2%
• D. 3%

Answer: (B)

Aniseikonia is the difference in how large images look to each eye, caused by unequal optical magnification from the corrective lenses. When the two eyes need different refractive powers, the lenses magnify the images by different amounts, so the brain receives images that aren’t the same size. The usual rule of thumb is that this differential magnification is about 1% for each diopter of power difference. So with a 1.00 D disparity between eyes, you’d expect roughly 1% aniseikonia. This estimate depends on factors like vertex distance and whether correction is via spectacles or contact lenses (contact lenses minimize magnification differences). The other options imply zero or larger-than-typical differences, which don’t align with this practical rule.

Aniseikonia is the difference in how large images look to each eye, caused by unequal optical magnification from the corrective lenses. When the two eyes need different refractive powers, the lenses magnify the images by different amounts, so the brain receives images that aren’t the same size. The usual rule of thumb is that this differential magnification is about 1% for each diopter of power difference. So with a 1.00 D disparity between eyes, you’d expect roughly 1% aniseikonia. This estimate depends on factors like vertex distance and whether correction is via spectacles or contact lenses (contact lenses minimize magnification differences). The other options imply zero or larger-than-typical differences, which don’t align with this practical rule.