Which is the least common non-strabismic binocular vision disorder?

• A. Convergence Insufficiency
• B. Convergence Excess
• C. Divergence Insufficiency
• D. Divergence Excess

Answer: (C)

Non-strabismic binocular vision disorders come from how well the eyes can converge for near and diverge for distance. Among these patterns, convergence insufficiency is the most common, while true divergence insufficiency is the least common. Divergence insufficiency means the eyes have trouble diverging to maintain single vision at distance, often showing distance exophoria with limited ability to use divergent fusional reserves. Most people’s vergence problems show up as near-demand issues (like convergence insufficiency or convergence excess) or as divergence excess patterns, so a true divergence insufficiency pattern is comparatively rare.