Study identifies most effective concentration of atropine for myopia control
A concentration of 0.05% atropine stymied the rate of myopia progression in preteen children compared with two other concentrations of the drug, according to findings published in Ophthalmology.
Jason C. Yam, FCOphthHK, FRCS (Edin), of the department of ophthalmology and visual sciences at the Chinese University of Hong Kong, and colleagues sought to evaluate the efficacy and safety of 0.05%, 0.025% and 0.01% atropine eye drops during a span of 2 years to ascertain the most useful concentration for long-term myopia control.
Yam and colleagues examined data from phase 2 of the randomized, double-masked LAMP study.
The researchers identified 383 children between 4 and 12 years old diagnosed with myopia of -1.0 D or greater who were stratified into groups receiving either atropine 0.05%, 0.025%, 0.01% or placebo once daily in both eyes in both phases of the study.
Children originally placed in the placebo group in phase 1 of the study were moved into the 0.05% atropine group, while the other children continued in their previously stratified groups, Yam and colleagues wrote. Cycloplegic refraction, axial length, accommodation amplitude, photopic and mesopic pupil diameter and best-corrected visual acuity were measured every 4 months.
The researchers sought primary outcomes of spherical equivalent and axial length changes and the differences between the three groups.
Yam and colleagues found at the end of year 2 that mean change spherical equivalent progression in the atropine 0.05% group (0.55 D; P = .015) was lower compared with the 0.025% group (0.85 D; P < .001). The mean spherical equivalent progression of the 0.01% atropine group was (1.12 D; P = .02).
In year 2, there was a similar efficacy between the 0.05% and 0.025% atropine groups compared with the first year (P > .1), the researchers wrote. They also observed a mild improvement in the 0.01% atropine group (P = .04).
In the placebo group, myopia progression was significantly reduced after switching to the 0.05% atropine group (spherical equivalent change, 0.18 D in year 2 vs. 0.82 D in year 1; P < .001), Yam and colleagues wrote. Axial length elongated 0.15 mm in the second year compared with 0.43 mm in the first year (P < .001).
“All concentrations of atropine were well tolerated without apparent adverse effects on the quality of life,” the researchers wrote. “The efficacy of 0.05% atropine observed was double that observed with 0.01% atropine in (spherical equivalent) progression over 2 years.”