Which binocular vision disorder is characterized by an exo deviation greater at near than distance and a low AC/A ratio?

Which binocular vision disorder is characterized by an exo deviation greater at near than distance and a low AC/A ratio?

• A. Convergence insufficiency
• B. Divergence excess
• C. Accommodative insufficiency
• D. Intermittent exotropia

Answer: (A)

Convergence insufficiency shows a pattern where the exodeviation is worse at near than at distance because the convergence system isn’t pulling the eyes inward as strongly when the demand is highest. The AC/A ratio describes how much vergence movement is driven by a given amount of accommodation. A low AC/A ratio means less convergence response to focusing up close, so the near task requires more convergence than the eyes can provide, leading to greater outward misalignment at near. This combination—near exodeviation greater than distance paired with a low AC/A ratio—fits convergence insufficiency most closely. Divergence excess would show the opposite pattern (larger deviation at distance) and often a high AC/A; accommodative insufficiency mainly affects clarity of vision rather than a consistent near exodeviation; intermittent exotropia involves variable control rather than a fixed near/distance difference with a low AC/A.

Convergence insufficiency shows a pattern where the exodeviation is worse at near than at distance because the convergence system isn’t pulling the eyes inward as strongly when the demand is highest. The AC/A ratio describes how much vergence movement is driven by a given amount of accommodation. A low AC/A ratio means less convergence response to focusing up close, so the near task requires more convergence than the eyes can provide, leading to greater outward misalignment at near. This combination—near exodeviation greater than distance paired with a low AC/A ratio—fits convergence insufficiency most closely. Divergence excess would show the opposite pattern (larger deviation at distance) and often a high AC/A; accommodative insufficiency mainly affects clarity of vision rather than a consistent near exodeviation; intermittent exotropia involves variable control rather than a fixed near/distance difference with a low AC/A.