angle of deviation

The angle formed between the visual axes of the fixating and the deviated eye when one eye is misaligned in strabismus. It can be measured subjectively using a synoptophore, where the patient superimposes first-degree targets, or objectively using the alternate cover test with prisms. The angle of deviation quantifies the magnitude of ocular misalignment and is essential for diagnosing and monitoring strabismus. Larger angles generally correlate with poorer binocular vision.