To evaluate the effect of patching on ocular alignment in children with unilateral amblyopia.

We evaluated the change in ocular alignment during and after patching in patients who had started amblyopia treatment with patching, and analyzed the aspects of change according to the cause and severity of amblyopia, type and magnitude of deviation, type of refractive error, and age at initiation. A change of eight prism diopters (PD) or more in horizontal deviation, or two PD or more in vertical deviation was considered significant.

A total of 209 patients were enrolled; 135 had amblyopia associated with anisometropia, 50 with strabismus, 19 with combined cause, and 5 with deprivation. After patching, there was no change in distant deviation in 177 patients (84.7%), while a decrease was noted in 23 patients (11.0%) and an increase in nine patients (4.3%). The angle of deviation decreased in 7.4% of anisometropic amblyopia, 20.0% of strabismic amblyopia, 10.5% of combined amblyopia, and 20.0% of deprivation amblyopia. The angle of deviation increased in 4.4% of anisometropic amblyopia, 5.3% of combined amblyopia, and 40.0% of deprivation amblyopia. The angle of deviation decreased in 24.2% of exodeviation, and 21.6% of esodeviation, but there was no change in vertical deviation among the studied patients. The angle of deviation decreased in 31.9% of patients with deviation greater than 8 PD. The change did not differ according to severity of amblyopia, type of refractive error, or age. Among the successes, decrease in deviation was more common until they achieved equal visual acuity between both eyes, while the increase during tapering of patching.

Change in ocular alignment may occur after patching in some patients with amblyopia, and seems to be more frequent in cases associated with horizontal deviation greater than 8 PD.