Which type of anomalous correspondence is least likely to produce diplopia?

• A. HAC
• B. UHAC
• C. PAC 1
• D. PAC 2

Answer: (A)

Anomalous retinal correspondence is the brain’s way of re-mapping where the two eyes’ images land on the retina so fusion can occur despite misalignment. The type that best preserves a single percept across a wide range of conditions tends to be the least likely to produce diplopia, because the adapted map of corresponding points keeps the inputs aligned enough for fusion even when the eyes are not perfectly aligned. This pattern provides the most stable binocular fusion, so you’re less likely to see diplopia.

By contrast, partial or less stable forms involve residual mismatches or more restricted alignment of corresponding points. Those configurations are more prone to producing diplopia, especially in certain gaze directions or when fusion is stressed. Hence, the form described here minimizes the chance of diplopia compared with the others.