What term describes a moderate to high refractive difference in powers?

The term that describes a moderate to high refractive difference in powers between the two eyes is anisometropia. This condition occurs when the two eyes have significantly different refractive errors, which can manifest as differences in nearsightedness (myopia), farsightedness (hyperopia), or astigmatism.

Anisometropia can lead to problems such as depth perception issues, visual discomfort, or binocular vision difficulties, as the brain struggles to fuse differing images from each eye. Clinicians need to be aware of this condition when fitting contact lenses, as it can influence lens selection and the overall approach to vision correction.

In contrast, myopia refers specifically to nearsightedness, hyperopia relates to farsightedness, and aniridia is a congenital condition involving the absence of the iris. While each of these terms describes a specific aspect of vision or eye anatomy, only anisometropia encompasses the concept of differing refractive powers between the two eyes.