Response to atropine for myopia progression is age dependent

A secondary analysis of data from the LAMP study assessed factors affecting response to 3 different concentrations of atropine in terms of change in spherical equivalent and elongation of axial length over a 2-year period.

Study design

This secondary analysis from the Low-Concentration Atropine for Myopia Progression (LAMP) study looked at the effect of treatment age and other factors on myopia progression depending on the use of 3 concentrations of atropine (0.05%, 0.025%, and 0.01%) in children aged 4–12 years. Three hundred fifty patients completed follow-up, and the primary endpoint was factors associated with spherical equivalent (SE) change and axial length (AL) elongation at 2 years.

Outcomes

At each year of age from 4 to 12 years, higher concentrations of atropine yielded better responses at all age groups for decreasing myopia progression. For all atropine concentrations, younger age at time of treatment was the factor most associated with poorer response (i.e., SE increase and AL elongation). For example, the mean for 2-year SE progression among 6-year-olds given 0.05% atropine was −0.90 D, comparable to progression among 8-year-olds given 0.025% atropine (−0.89 D) and 10-year-olds given 0.01% atropine (−0.92 D).

Limitations

Some environmental factors for myopia progression, including near work and outdoor activity, were assessed with validated questionnaires. Also, in the original study, patients randomized to placebo were converted after the first year to receive 0.05% atropine; thus, in this 2-year analysis, there was no control group.

Clinical significance

Since younger age is associated with a poorer myopia progression response to atropine treatment, younger children need higher concentrations of atropine in order to slow myopia progression at the same rate as older children on lower concentrations.