Abstract
Purpose: :
To determine whether child age influences the magnitude of response to amblyopia treatment.
Methods: :
Multivariate linear regression models were fit using a meta-analysis of individual patient data from 4 recently completed randomized trials to evaluate the relationship between age and improvement in amblyopic eye acuity. Study treatments were: 2 h/d patching with near vs distance activities in 3 to <7 year olds, atropine with and without a plano lens in 3 to <7 year olds, Bangerter filters vs part-time daily patching in 3 to <10 year olds and atropine vs patching 2h/d in 7 to <13 years olds. The studies were of similar duration and visual acuity was measured using standardized methods by masked examiners. The regression models adjusted for baseline amblyopic eye acuity, spherical equivalent refractive error in the amblyopic eye, prior amblyopia treatment, study treatment and protocol. The outcome measure was lines of improvement of visual acuity (logMAR) and age strata were compared using the Tukey-Kramer multiple comparisons test with a significance level of p<0.05.
Results: :
For moderate amblyopia (20/40 to 20/100), there was a significant, non-linear association between younger age and improvement in amblyopic eye acuity (p<0.001).There were no significant differences in treatment response among subjects age < 7 years (3 to <4 years, 4 to < 5, 5 to <6, 6 to <7), but these younger age groups were more responsive than the older age groups (7 to <8, 8 to <10, and 10 to <13). For severe amblyopia (20/125 to 20/400), younger age was also significantly associated with improvement in amblyopic eye acuity (p<0.0001), but the effect was more gradual across the entire age range and the oldest children (7 to <13 years) were least responsive. There was no evidence that the age effect on treatment response differed by treatment among protocols with overlapping age groups (patching vs atropine vs Bangerter in moderate amblyopia and patching vs atropine in severe amblyopia).
Conclusions: :
For both moderate and severe amblyopia, children ages 7 to <13 years were least responsive to treatment. Treatment response was similar among younger children (3 to <7 years) with moderate amblyopia, but there was a more gradual decrease in responsiveness across the 3 to <13 age range for severe amblyopia. Based on these results, amblyopia should be detected and treated as soon as possible, particularly if severe, although many individual older children still respond to therapy if detection and treatment are delayed.
Clinical Trial: :
www.clinicaltrials.gov NCT00315198, NCT00315302, NCT00315328, NCT00525174
Keywords: amblyopia • visual acuity • visual development: infancy and childhood