Anisometropia with astigmatism as an amblyogenic factor is defined by a diopter difference greater than what value between the eyes?

• A. -2.00D
• B. -1.50D
• C. -0.50D
• D. -3.00D

Answer: (B)

Anisometropia refers to a different refractive power between the two eyes. When astigmatism is present as an amblyogenic factor, the risk of developing amblyopia rises even at smaller differences because the blur differs by meridian between the eyes, making binocular fusion harder during development. The clinically used threshold for defining amblyogenic anisometropia in this context is an interocular difference of more than 1.50 diopters. So if the eyes differ by more than 1.50 D, this situation is considered amblyogenic anisometropia with astigmatism. The other values don’t fit this criterion, since they are either smaller than the amblyogenic threshold or not the commonly cited cutoff in this scenario.