Factors contributing to the outcome of sensory testing in patients with anomalous binocular correspondence

Traditional teaching on anomalous retinal correspondence (ARC) identifies the dissociative quality of a sensory test as the primary factor influencing the outcome of correspondence testing. However, these tests differ also in function and format. This study compared one mildly dissociating test and one highly dissociating test to evaluate the subjective visual direction of both the deviation point and the fovea of the deviating eye in 74 patients with ARC. Subjects were more likely to demonstrate an ARC response, and to do so after a significantly shorter period of time following change in alignment, on the minimally dissociating tests. Eighty-five percent demonstrated the presence of a pseudo-fovea at the deviation point, while only 39% had evidence of rewiring of the deviated fovea. The mean angle of deviation of the latter group was significantly larger than that of the former group (P < 0.001). Exotropic patients were more likely to rewire the fovea than esotropic patients (P < 0.005). The mean time needed to rewire a pre-existing ARC following a change in deviation was 7.7 ± 1 months. Results of this study indicate that variables influencing sensory test results include: a) retinal element evaluated, b) magnitude of the deviation, c) direction of the deviation, and d) age of onset of the strabismus. Results of sensory testing in patients with ARC may be misinterpreted if these factors are not taken into consideration.