The Effect of Amblyopia Treatment with Patching on Ocular Alignment

Abstract

This study was 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.

한 눈 약시에서 가림치료가 안구정렬에 미치는 영향을 알아보고자 하였다. 가림치료를 처음 시행한 한눈 약시 환아를 대상으로, 가림치료 전, 두 눈 시력이 같아진 시점, 가림치료 후에 안구편위를 측정하여 비교하고, 약시 종류와 정도, 편위 종류와 정도, 굴절이상 종류, 가림치료 시작나이에 따른 차이가 있는지 살펴보았다. 수평 사시각은 8프리즘디옵터(prism diopter, PD) 이상, 수직 사시각은 2PD 이상의 차이가 있으면 의미 있는 변화로 정하였다. 총 209명은 굴절부등약시 135명, 사시약시 50명, 혼합약시 19명, 시각차단약시 5명이었다. 가림치료 후 원거리 안구편위는 177명(84.7%)에서 변화가 없었으나, 23명(11.0%)에서 감소, 9명(4.3%)에서 증가하였다. 굴절부등약시의 7.4%, 사시약시의 20.0%, 혼합약시의 10.5%, 시각차단약시의 20.0%에서 편위각이 감소하였고, 굴절부등약시의 4.4%, 혼합약시의 5.3%, 시각차단약시의 40.0%에서 편위각이 증가하였다. 외편위의 24.2%, 내편위의 21.6%에서 편위각이 감소하였으나, 수직편위는 변하지 않았다. 8PD가 넘는 편위가 있었던 환아의 31.9%에서 편위각이 감소하였다. 약시 정도, 굴절이상 종류, 나이에 따른 편위 변화의 차이는 없었다. 가림치료에 성공한 경우, 편위각 감소는 두 눈 시력이 같아질 때까지, 증가는 가림치료를 감량하는 동안 많이 나타났다. 일부 약시 환아에서 가림치료 전후 안구정렬에 변화가 생길 수 있으며, 8PD가 넘는 수평사시를 동반한 경우에 상대적으로 흔하였다.