anomalous retinal correspondence
A sensory adaptation in strabismus where the fovea of the fixating eye corresponds with an eccentric retinal area in the deviated eye, allowing the eyes to work together without diplopia. In harmonious ARC, the angle of anomaly equals the objective angle of deviation. In unharmonious ARC, the angle of anomaly is smaller than the objective angle. ARC can be confirmed using afterimage testing or the synoptophore.