anomalous retinal correspondence

Anomalous retinal correspondence (ARC) is a sensory adaptation to a constant strabismus in which the fovea of the fixating eye acquires a common visual direction with a peripheral area of the deviated eye. The two foveae then no longer share a visual direction.¹ ARC develops in children, whose plastic visual systems can shift correspondence to compensate for the strabismus and restore some binocular cooperation.^1,2

The angle of anomaly is the angle through which correspondence has shifted from normal.² In harmonious ARC, the angle of anomaly equals the objective angle of deviation, so the subjective angle is zero and the sensory adaptation is complete. In unharmonious ARC, the angle of anomaly is smaller than the objective angle, and the adaptation is incomplete.¹

The afterimage test, the Bagolini striated glasses test and the major amblyoscope are the tests most often used for retinal correspondence.¹ Harmonious ARC gives single vision. Unharmonious ARC is exceedingly rare, and many early test methods created artificial conditions that broke harmonious ARC down and mimicked the unharmonious form.²