CONJUGACY OF SACCADES IN DEEP AMBLYOPIA

Purpose. To determine the degree of conjugacy of saccades in humans wi th one deeply amblyopic eye, to assess whether Hering's law requires g ood binocular visual acuity. Methods. By means of magnetic search coil s, horizontal saccades were recorded accurately in 11 subjects with un ilateral, deep amblyopia. The recordings were compared to those made i n ii normal subjects. In addition, three subjects with amblyopia were submitted to artificial anisometropia, which called for nonconjugate a daptation of their saccades. Results. The saccades of most subjects wi th amblyopia were nonconjugate. These nonconjugacies often were larger in one direction than in the opposite one. The magnitude of the nonco njugacies varied inconsistently with the size of the saccades. In addi tion, the amblyopic eye often showed conspicuous drift. The saccades a dapted nonconjugately to the imposed anisometropia. Conclusions. In de ep amblyopia, the two eyes often make saccades that are unequal in siz e. The amblyopic eye does not move aimlessly, roughly following the mo vements of the normal fellow eye. Instead, the saccades of the amblyop ic eye appear to reflect a deliberate oculomotor strategy, bringing vi sual targets to presumed retinal points of preference.