Purpose: The aim of this study is to determine if topical atropine, used to retard axial length elongation and myopia progression, has any effect on ocular astigmatism.
Methods: Data collected from subjects enrolled in the Atropine in the Treatment of Myopia (ATOM) study was analysed. In this study, 400 myopic children (aged 6-12 years) were randomly assigned to administer atropine 1% or a placebo daily to a randomly selected eye for two years. Cycloplegic autorefraction and keratomy readings were measured using a Canon RK5 autorefractor. The refractive error was then split into its power vectors components; J0 and J45.
Results: Astigmatism increased by 0.12-0.16D per year in both treated and placebo groups. There was no difference between groups (p=0.182). The increase was mirrored by an increase in corneal astigmatism of 0.10-0.13 D per year suggesting that most of the change was corneal in nature. There was an increase in JO vector (ie. with-the-rule astigmatism) with no change in the J45 (oblique) vector over time. The change in the J0 vector was significantly larger in the atropine-treated versus atropine-untreated eyes during the 2 year treatment period (p=0.016) but this difference disappeared after atropine was stopped.
Conclusion: The use of atropine on a daily basis over two years did not have any clinically significant effect on astigmatism.