The effect on refractive error of unilateral atropine as compared with patching for the treatment of amblyopia

Our objective was to determine whether the use of unilateral atropine as amblyopia therapy leads to an asymmetric change in refractive error compared with patching. Patients were enrolled in a clinical trial in which atropine 1% solution or occlusion with an adhesive patch was administered daily to the sound eye of children 3 to less than 7 years of age for a period of at least 6 months to a maximum of 2 years. Refractive error at entry and at 2 years was determined with cycloplegic retinoscopy for 282 of 419 patients enrolled. The baseline mean refractive error was + 3.13 diopters (D) in patients assigned randomly to receive atropine and + 2.58D in patients assigned randomly to wear the patch. The mean change in refractive error of the sound eye was + 0.10 D in the atropine group (N = 134) and + 0.08 D in the patch group (N = 148). Patients also were subdivided into those treated with atropine only (n = 41) and patching only (n = 64) because some children changed treatments during their study participation. The mean change for the sound eyes was -0.21 D for the patients receiving only atropine and -0.06 D for the patients receiving only patching. Unilateral atropine applied to the sound eye compared with occlusion was not associated with any adverse effect on refractive error following up to 2 years of treatment.