Abstract
Purpose:
To evaluate the degree and time course of amblyopia improvement with 2 hours of daily patching in children age 3 to less than 8 years with strabismic and/or anisometropic amblyopia, and to determine predictors of visual acuity improvement in the amblyopic eye.
Methods:
200 children age 3 to less than 8 years with strabismic and/or anisometropic amblyopia who had no prior patching therapy were enrolled into the run-in phase of a clinical trial. Prior to enrollment, children wore spectacles (if needed) for at least 16 weeks or until there was no improvement in amblyopic eye acuity between 2 visits at least 4 weeks apart. At enrollment into the run-in phase, 2 hours of daily patching was prescribed for at least 12 weeks and until there was no improvement in amblyopic eye acuity between 2 visits at least 6 weeks apart, confirmed by a re-test.
Results:
Children with moderate amblyopia (20/50 to 20/80 at enrollment, n=139) improved an average of 2.9 log MAR lines, and those with severe amblyopia (20/100 to 20/400 at enrollment, n=61) improved an average of 4.9 lines. Amblyopic eye acuity improved to 20/25 or better and was within one line of the fellow eye for 35% (95% CI = 27%, 44%) with moderate amblyopia and for 13% (6%, 24%) with severe amblyopia. Nearly half of children with either moderate (49%) or severe (48%) amblyopia achieved their best amblyopic eye acuity within 12 weeks of initiating patching. Some children required up to 50 weeks of patching 2 hours daily before they stopped improving. Greater amblyopic eye acuity improvement was associated with worse acuity (p<0.001) and younger age (p=0.025) at baseline.
Conclusions:
For many children age 3 to less than 8 years with strabismic and/or anisometropic amblyopia and no prior patching, 2 hours of daily patching leads to robust improvement in visual acuity. Worse enrollment acuity and younger age at the start of patching treatment are associated with more lines of improvement in amblyopic eye acuity. After an initial period of spectacle treatment of amblyopia, it is reasonable to initiate patching at a dosage of 2 hours each day, even for children with severe amblyopia.