Atropine eye drops have demonstrated good efficacy in combating the myopia epidemic. Although previous studies have found positive results with low-dose formulations, researchers recently reported that younger age is associated with poorer treatment outcomes to lower concentrations of the drug.

This secondary analysis included 350 children (ages four to 12 years old), who were randomly assigned to receive 0.05%, 0.025% or 0.01% atropine or placebo once daily in both eyes. In the second year, the placebo group was switched to 0.05% atropine.

In the 0.05%, 0.025% and 0.01% atropine groups, younger age was the only factor associated with spherical equivalent progression and axial length elongation; the younger the patient, the poorer their response. Higher-concentration atropine showed a better treatment response with each increasing year of age, following a concentration-dependent effect.

To illustrate this effect, the researchers noted that the mean spherical equivalent progression in six-year-old children taking 0.05% atropine was similar to that of eight-year-olds in the 0.025% atropine group and 10-year-olds in the 0.01% atropine group. All concentrations were well tolerated at all age groups.

“Among the atropine concentrations studied, younger children required the highest concentration (0.05%) to achieve a similar reduction in myopic progression as older children on lower concentrations,” the study authors concluded in their paper.

Despite the current recommendation of stepwise increases in atropine concentration starting with 0.01% if treatment response is suboptimal, the investigators suggested administering a higher concentration as a starting dosage in younger children, especially given their greater predisposition to myopia progression. “When 0.05% atropine is used as such, the age difference at which a similar efficacy can be achieved using other concentrations amounts to two years compared with 0.025% atropine, four years compared with 0.01% atropine and six years compared with the placebo, within the age ranges from four to 12,” they wrote.