Five-Year Clinical Trial of the Low-Concentration Atropine for Myopia Progression (LAMP) Study: Phase 4 Report

Purpose: To evaluate (1) the long-term efficacy of low-concentration atropine over 5 years, (2) the proportion of children requiring re-treatment and associated factors, and (3) the efficacy of pro re nata (PRN) re-treatment using 0.05% atropine from years 3 to 5.

Design: Randomized, double-masked extended trial.

Participants: Children 4 to 12 years of age originally from the Low-Concentration Atropine for Myopia Progression (LAMP) study.

Methods: Children 4 to 12 years of age originally from the LAMP study were followed up for 5 years. During the third year, children in each group originally receiving 0.05%, 0.025%, and 0.01% atropine were randomized to continued treatment and treatment cessation. During years 4 and 5, all continued treatment subgroups were switched to 0.05% atropine for continued treatment, whereas all treatment cessation subgroups followed a PRN re-treatment protocol to resume 0.05% atropine for children with myopic progressions of 0.5 diopter (D) or more over 1 year. Generalized estimating equations were used to compare the changes in spherical equivalent (SE) progression and axial length (AL) elongation among groups.

Main outcomes measures: (1) Changes in SE and AL in different groups over 5 years, (2) the proportion of children who needed re-treatment, and (3) changes in SE and AL in the continued treatment and PRN re-treatment groups from years 3 to 5.

Results: Two hundred seventy (82.8%) of 326 children (82.5%) from the third year completed 5 years of follow-up. Over 5 years, the cumulative mean SE progressions were -1.34 ± 1.40 D, -1.97 ± 1.03 D, and -2.34 ± 1.71 D for the continued treatment groups with initial 0.05%, 0.025%, and 0.01% atropine, respectively (P = 0.02). Similar trends were observed in AL elongation (P = 0.01). Among the PRN re-treatment group, 87.9% of children (94/107) needed re-treatment. The proportion of re-treatment across all studied concentrations was similar (P = 0.76). The SE progressions for continued treatment and PRN re-treatment groups from years 3 to 5 were -0.97 ± 0.82 D and -1.00 ± 0.74 D (P = 0.55) and the AL elongations were 0.51 ± 0.34 mm and 0.49 ± 0.32 mm (P = 0.84), respectively.

Conclusions: Over 5 years, the continued 0.05% atropine treatment demonstrated good efficacy for myopia control. Most children needed to restart treatment after atropine cessation at year 3. Restarted treatment with 0.05% atropine achieved similar efficacy as continued treatment. Children should be considered for re-treatment if myopia progresses after treatment cessation.

Financial disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article.