The course of moderate amblyopia treated with atropine in children: experience of the amblyopia treatment study.

PURPOSE

To assess the course of the response to atropine treatment of moderate amblyopia and to assess factors predictive of the treatment response in children 3 years old to younger than 7 years old.

DESIGN

Multicenter, randomized clinical trial comparing atropine and patching (one of the amblyopia treatment studies).

METHODS

A total of 195 children 3 years old to younger than 7 years of age with amblyopia in the range of 20/40 to 20/100 from the atropine treatment arm of this trial were enrolled and included in this analysis. At baseline, daily topical atropine was prescribed for the sound eye. During follow-up, a plano spectacle lens was prescribed for the sound eye for patients whose amblyopia had not been successfully treated with atropine alone. Follow-up examinations were performed at 5 weeks, 16 weeks, and 6 months. The primary outcome measure was visual acuity in the amblyopic eye at 6 months.

RESULTS

Mean visual acuity improved from baseline by 1.3 lines after 5 weeks of treatment, by 2.4 lines after 16 weeks, and by 2.8 lines at 6 months. Visual acuity of 20/30 or better and/or 3 or more lines of improvement from baseline was achieved by 75% of the patients. Improvement occurred over the entire range of baseline acuities (20/40 to 20/100) and was not related to patient age (P =.36). Among the 134 patients improving 3 or more lines from baseline, 7% achieved their maximum improvement by 5 weeks and 46% by 16 weeks. Among the 55 patients who did not respond adequately to atropine alone and were prescribed a plano lens for the sound eye, the mean improvement before the use of the plano lens was 1.0 lines, compared with 1.6 lines after prescribing the plano lens (P =.11). None of the demographic or clinical factors assessed was predictive of the response to treatment. A shift in fixation preference at/near from the atropinized sound eye to the amblyopic eye was not required for the amblyopic eye to improve; amblyopic eye acuity improved 3 or more lines in 29 (60%) of the 48 patients who were found to be using the atropinized sound eye on fixation preference testing. A 2 or more line decrease in sound eye visual acuity occurred more frequently when a plano lens was prescribed in addition to atropine (7 of 43, 16%) compared with treatment with atropine alone (4 of 123, 3%; P =.01).

CONCLUSIONS

A beneficial effect of atropine is present throughout the age range of 3 years old to younger than 7 years old, and with an acuity range of 20/40 to 20/100. A shift in near fixation to the amblyopic eye is not essential for atropine to be effective in all cases. Sound eye acuity should be monitored when a plano spectacle lens is prescribed for the sound eye to augment the treatment effect of atropine.