Phoria, vergence, and fixation disparity in oculomotor problems.

Measures of horizontal phoria, vergence, and fixation disparity were obtained for 2 samples: 28 optometry students without symptoms and 32 orthoptic patients with symptoms associated with binocular oculomotor difficulties. Discriminant analysis was used to determine which tests or group of tests best discriminated between the 2 samples. Analysis was done for both samples and for exophoric and esophoric subsamples. Sheard's criterion was the best discriminator for the exophoric group, and amount of heterophoria was the best discriminator for the esophoric group. Fixation disparity was the next best discriminator for both groups.