Effect of Low-Concentration Atropine Eye Drops on Parapapillary Gamma Zone Development and Enlargement over 3 Years: The LAMP Study

Purpose To evaluate the longitudinal changes in the parapapillary gamma zone in children receiving 0.05%, 0.025%, 0.01% atropine eyedrops and placebo/switchover over 3 years based on the Low-Concentration Atropine for Myopia Progression (LAMP1) study. Design Secondary analysis from a randomized controlled trial. Participants 280 children underwent spectral domain optical coherence tomography (SD-OCT) at baseline, which involved 24 equally spaced radial OCT B-scans of the optic nerve head, taken at one-year intervals. Methods Children in the LAMP1 study were randomized to receive 0.05%, 0.025%, 0.01% atropine, or placebo eyedrops. In the second year, placebo participants switched to 0.05% atropine. At the beginning of the third year, each group was re-randomized to continued treatment or cessation (washout). The Bruch's membrane opening (BMO) was identified in 48 meridians in each eye. Gamma zone was defined as the parapapillary region without Bruch's membrane. Main Outcome Measures Differences between treatment groups in gamma zone area changes from baseline to the 3-year follow-up visits. Results Out of 238 children included at baseline, the study included 192 (80.7%) children completing the follow-up of 3 years. The cumulative mean gamma zone area changes differed significantly between the initial 0.05%, 0.025%, and 0.01% atropine subgroups (0.09±0.09mm 2 , 0.19±0.12mm 2 , and 0.22±0.17mm 2 ; P for trend