Anisometropia is a condition in which:

Anisometropia refers to a condition where each eye has a different degree of refractive error. This means that one eye may be nearsighted, farsighted, or have astigmatism to a different extent than the other eye. This disparity can lead to visual discomfort and issues with depth perception, as the brain receives differing visual information from each eye. Individuals with anisometropia may struggle to fuse the images from both eyes into a single, cohesive picture, which is essential for clear and comfortable vision.

The other options are incorrect because they either suggest that the refractive errors are similar in both eyes, indicate no refractive error at all, or fall outside the correct definition of anisometropia. Option A states that each eye has the same refractive error, which describes isometropia, not anisometropia. Option B implies that neither eye has a refractive error, which does not relate to anisometropia. Option D, which states "none of the above," is also incorrect because option C correctly defines the condition. Hence, the understanding of anisometropia is crucial for proper recognition, diagnosis, and management in ophthalmic practice.