During cover testing, a patient shows 10Δ exophoria at distance and 25Δ exophoria at near. The MOST likely diagnosis is:
A. Convergence insufficiency ✔️
B. Divergence excess
C. Basic exotropia
D. Accommodative spasm
Explanation: Convergence insufficiency is characterized by a remote near point of convergence and greater exodeviation at near than distance. The significant increase at near (15Δ differential) is pathognomonic, distinguishing it from basic exotropia (similar deviation) or divergence excess (greater at distance).