Which of the following best describes meridional amblyopia?

Which of the following best describes meridional amblyopia?

• A. Caused by uncorrected astigmatism and persists after correction
• B. Caused by anisometropia
• C. Caused by strabismus
• D. Caused by form deprivation

Answer: (A)

Meridional amblyopia is a type of amblyopia tied to astigmatic blur that runs along a single meridian. When astigmatism is uncorrected during the critical period of visual development, the image is consistently blurred in one orientation, and the brain learns to suppress or under-activate information from that orientation. This creates a directional (meridional) loss of acuity that is not uniform across all orientations. If the eye is later corrected with glasses, the blur is reduced, but the neural adaptations can persist, so the amblyopia may remain to some extent. The choice that captures this by saying it is caused by uncorrected astigmatism and can persist after correction best describes meridional amblyopia. The other options point to different mechanisms—anisometropia, strabismus, or form deprivation—that produce amblyopia through other pathways and do not define meridional amblyopia's orientation-specific origin.

Meridional amblyopia is a type of amblyopia tied to astigmatic blur that runs along a single meridian. When astigmatism is uncorrected during the critical period of visual development, the image is consistently blurred in one orientation, and the brain learns to suppress or under-activate information from that orientation. This creates a directional (meridional) loss of acuity that is not uniform across all orientations. If the eye is later corrected with glasses, the blur is reduced, but the neural adaptations can persist, so the amblyopia may remain to some extent. The choice that captures this by saying it is caused by uncorrected astigmatism and can persist after correction best describes meridional amblyopia. The other options point to different mechanisms—anisometropia, strabismus, or form deprivation—that produce amblyopia through other pathways and do not define meridional amblyopia's orientation-specific origin.