A strabismus must be Constant and Unilateral in order for it to be considered an amblyogenic factor.

• A. Constant and Unilateral
• B. Intermittent and Bilateral
• C. Constant and Bilateral
• D. Intermittent and Unilateral

Answer: (A)

Amblyopia develops when one eye’s visual input is suppressed for a prolonged period during the critical period of visual development. This suppression happens most reliably when the strabismus is constant and unilateral: the misaligned eye is consistently deviated and the brain suppresses its input to avoid diplopia, leading to reduced visual acuity in that eye. If the misalignment is intermittent, there are periods of normal alignment and potential fusion, so suppression and abnormal visual experience aren’t sustained long enough to produce amblyopia. Bilateral strabismus lacks a single eye that is consistently suppressed, so the classic unilateral amblyopic pattern is less likely. Therefore, constant and unilateral strabismus is the amblyogenic pattern.