JCHR

Occlusion versus Pharmacologic Therapy for Moderate Amblyopia

Protocol

Recruitment began in April 1999 and closed in April 2001 after 419 patients were enrolled. Six-month follow-up (primary outcome exam) was completed in November 2001. Two year follow up of patients was completed in July 2003. Extended follow up of study patients with visits at age 10 years was completed in August 2007.  Extended follow up of study patients is ongoing with visits at age 15. For more information click here: Long Term Follow up of Amblyopia Treatment

Objective:
To compare patching and atropine as treatments for moderate amblyopia in children less than 7 years of age over a two-year follow-up period.

Six Month Results:
Between April 1999 and April 2001, 419 patients entered the trial, with 215 assigned to the patching group and 204 to the atropine group. The mean visual acuity in the amblyopic eye at enrollment was approximately 20/63, with a mean difference in acuity between eyes of 4.4 lines. The average age of the children was 5.3 years; 47% were girls and 83% Caucasian.
At six months, visual acuity was improved from baseline by about 3 lines of vision in both the atropine and patching groups.

Improvement initially was faster in the patching group, but after six months, the difference in acuity between treatment groups was small. The mean visual acuity (Snellen approximation) at six months was 20/32 in the patching group and 20/32-2 in the atropine group. This small difference between groups was considered clinically inconsequential.

Both treatments were well tolerated, although atropine had a slightly higher degree of acceptability on a parental questionnaire. More patients in the atropine group than in the patching group had reduced acuity in the sound eye at six months but this did not persist with further follow up.

Both atropine and patching are effective treatments for moderate amblyopia in children in the age range of 3 to less than 7 years old. Patching has the potential advantage of a more rapid improvement in visual acuity and possibly a slightly better acuity outcome, whereas atropine has the potential advantage of easier administration and lower cost. Our data are inconclusive about whether atropine may cause a transient treatment-related reduction of acuity in the sound eye more often than does patching. However, we are reasonably confident that in our cohort atropine did not have a lasting adverse effect on acuity of the sound eye. Since incomplete responders to one treatment could later be given the other treatment, our results indicate that the initial choice of patching or atropine can be made by the eye care provider and parent. Both patching and atropine are appropriate treatment modalities for the initial management of moderate amblyopia in children.

Two Year Results:
At 2 years, visual acuity in the amblyopic eye improved from baseline an average of 3.7 lines in the patching group and 3.6 lines in the atropine group. The difference in visual acuity between treatment groups was small, 0.01 logMAR (95% confidence interval, -0.02 to 0.04). In both treatment groups, the mean amblyopic eye acuity was approximately 20/32, 1.8 lines worse than the mean sound eye acuity, which was approximately 20/20.

Atropine or patching for 6 months followed by best clinical care until 2 years produced similar improvement of moderate amblyopia in children between 3 and 7 years of age at enrollment. However, on average the amblyopic eye was still about 2 lines worse than the sound eye.

Ten Year Results:
At age 10 years, the improvement of the amblyopic eye is maintained, although residual amblyopia is common after treatment initiated at age 3 years to younger than 7 years. The outcome is similar regardless of initial treatment with atropine or patching.

The monocular oral reading ability when measured with the GORT-4 was slightly worse when reading with previously treated amblyopic eyes compared with fellow eyes in terms of rate, accuracy, and fluency, but reading comprehension testing was similar.

Following treatment for amblyopia initiated at age 3 to 6 years, contrast sensitivity at age 10 years is slightly worse in amblyopic eyes compared with fellow eyes.