Ophthalmology, August 2021
Although low-dose atropine has shown promise for myopia control in children, the responses to treatment vary widely. In the Low-Concentration Atropine for Myopia Progression (LAMP) study, the spherical equivalent (SE) reductions over one year ranged from 27% to 67% for atropine concentrations of up to 0.05%. In a secondary analysis of LAMP data, Li et al. aimed to elucidate factors related to poor treatment response. They found that younger age predicts lower response, whereas baseline SE and parental myopia status did not affect the responses.
Of the original 438 children recruited for the LAMP study, 350 completed two years and were included in the follow-up study. Patients were categorized by age (4-6 years, 7-9 years, and 10-12 years) and were assigned randomly to receive atropine 0.05%, 0.025%, 0.01%, or placebo. In the second year, those initially given placebo received 0.05% atropine. Generalized estimating equations were used to evaluate potential predictors of change in SE and axial length (AL); these included age, gender, baseline refraction, parental myopia status, and other factors.
During both years of treatment, younger age was the only predictor of faster SE progression and AL elongation; the youngest group had the weakest treatment response. During the two-year period, myopia progression of 10-year-olds in the 0.01% group was similar to that of 8-year-olds in the 0.025% group and of 6-year-olds in the 0.05% group. For each younger-age year, the mean SE change was 0.14 D larger in the 0.05% group, 0.15 D larger in the 0.025% group, and 0.20 D larger in the 0.01% group. Although age and atropine concentration were significant risk factors for SE progression and AL elongation, there was no interaction between the two, indicating that they influence myopia progression independently.
All concentrations of atropine were well tolerated, regardless of age. The mean accommodation amplitude decreased with age, but the mean changes in photopic pupil size were similar among treatment and age groups, as were the rates of photophobia and use of photochromic glasses. These results suggest that among the factors studied, age was the only predictor of response to atropine treatment. For children under 7 years of age, the highest concentration (0.05%) is required to attain efficacy similar to that of smaller doses in older children. (Also see Clinical Update, page 30.)
The original article can be found here.