Patch or atropine? Either offers lasting benefits in amblyopia

Either patching or atropine sulfate 1% to occlude the sound eye offers lasting benefits to patients with amblyopia, accordingto Michael X. Repka, MD, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore.Atropine is not approved for use in amblyopia, he said.

Dr. Repka reported on his participation in a randomized, controlled, multicenter trial. The study had two goals: to seewhether there was merit to the use of atropine in patients with amblyopia, and also to see whether the benefit that wasacquired from amblyopic therapy-whether from atropine or patching-was sustained over time. Primary outcomes ofthe study were at 6 months, 2 years after enrollment, and at patient age 10 and 15 years. The study enrolled 419 patients;all had strabismic or anisometropic amblyopia.

Patching dose was set at 6 or more hours per day, and atropine was administered one drop per day, in the morning, in thesound eye. If the patients had not achieved 20/30 vision within 4 months, therapy was intensified to waking hour patching(patching group) or usage of a plano lens (atropine group).

At 6 months, the mean acuity had improved to 20/30-2 in the atropine group and 20/30 in the patching group. The patchinggroup improved faster; at 5 weeks there was a statistically significantly better acuity. Both groups, however, continued toimprove for 6 months.

"We didn't expect that strabismic amblyopes would succeed with atropine. Why would you ever switch fixation?" Dr. Repka said."Yet, that's not what we saw. The strabismic patients were as likely to succeed as the anisometropic patients. That wentagainst everything we intuitively knew."

Also, patients were as likely to improve the same amount if they entered the study at 20/100 as those who entered at 20/40.Some detrimental effects occurred on the sound eye with atropine, however. A decrease in visual acuity of one line or moreoccurred significantly more often in the atropine group (23%) than in the patching group (8%).The benefits of treatment persisted in both groups.

"The mean improvement after in both groups could not have been more remarkably similar after 2 years," Dr. Repka said. "About85% of the overall patient population had achieved 20/32, or a three line or better improvement. There was a substantialimprovement from either therapy, and it's not limited to the first 5 weeks or the first 6 months. Rather, it's an ongoingprocess that requires a great deal of supervision and monitoring."