Astigmatism Increases With Atropine Treatment, Despite Myopia Slowing Efficacy

While atropine 0.01% treatment has demonstrated an ability to slow myopia progression in children with myopia, astigmatism increases with atropine treatment, according to research published in Heliyon.

Researchers included 119 eyes with myopia (spherical equivalent [SE], -0.50 to -6.00 diopters [D], total astigmatism > -2.00 D]) in the single-center study and randomly assigned participants to once-nightly atropine 0.01% treatment (n=69; 50.5% girls; mean age, 8.91 years) or a control group treated with single vision spectacle lenses (n=50; 65.3% girls; mean age, 8.28 years). Study participants underwent comprehensive eye examinations and ocular biometric parameter testing at baseline, 3, 6, and 9 months. The investigators evaluated potential astigmatism increases with respect to total, corneal, and residual astigmatism.

At the 9-month follow-up visit, participants who were treated with atropine 0.01% demonstrated less myopia progression compared with control group individuals (SE: −0.35 vs −0.56 D; P =.001; axial length: 0.20 vs 0.33 mm; P <.001). A total of 1.5% of eyes treated with atropine 0.01% experienced SE progression of more than 1 D compared with 22% of eyes exclusively treated with single vision spectacle lenses (P <.001). There were no significant differences in anterior chamber depth, lens thickness, or central corneal thickness measurements between the 2 groups at any of the follow-up visits.

However, the report shows that astigmatism increases with atropine treatment. Individuals treated with atropine 0.01% showed a significant increase in total astigmatism compared with individuals who were exclusively treated with single vision lenses (−0.14 vs −0.04 D). This change in total astigmatism among individuals undergoing atropine 0.01% treatment was primarily the result of corneal astigmatism changes (−0.17 D) — residual astigmatism changes were minimal (−0.02 D).

“Differences in changes in astigmatism and the relationship with myopic progression between atropine-treated eyes and control eyes might have resulted from changed contractile responses of the ciliary body during atropine treatment,” the researchers suggest. “Moreover, atropine could have potential effects on the cornea, conjunctiva, lens, or sclera due to the presence of multiple muscarinic acetylcholine receptors in all these tissues.”

Study limitations include a single center design, small sample size, and a short study duration.