Abstract
Purpose :
Childhood myopia is a common vision disorder that affects a significant portion of children. Low-dose Atropine is successfully applied to slow the progression of myopia, however, its mechanism has not yet been fully understood. As part of the SAM IIT trial possible effects of daily topical administration of 0.01% Atropine on the morphology of the ciliary muscle were investigated.
Methods :
As part of the SAM IIT trial, 23 children (8–15 yrs., 14 female) were analysed in the study (inclusion criteria: 6-17 yrs., myopia progression ≥ 0.5D/yr., SER<-4D, BCVA≤0.1 logMAR). After the baseline visit, 0.01% Atropine was administered first into one eye, followed by visit 1. Parents were instructed to put eye drops in both eyes every evening. During follow-up visits after 1 week, 6, 12, and 13 months, the right eye’s ciliary muscle was imaged using AS-OCT according to Wagner (2018) (accommodative demands: 4D, 2D). Images were automatically segmented (Straßer 2022) and the perpendicular axis (PA, Fig. 1) was determined (Wagner 2018, Straßer 2020) and analyzed using a linear mixed-effects model with SEX, VISIT, M_DUR, ACC_DEMAND, and relevant interactions as fixed effects, and the subject as random effect. Additionally, CM thickness (CMT) profiles in relation to the effects of the linear model were evaluated using functional data analysis (FDA).
Results :
Statistically significant effects were found for ACC_DEMAND, VISIT (Fig. 2), M_DUR, and interactions of SEX with M_DUR, VISIT, and ACC_DEMAND (Table 1). Females show a PA increase rate of 1.4 µm, males of 28.9 µm per year. A post hoc analysis using Dunnett’s test revealed a statistically significant difference of 23.8 µm between baseline and visit 1 (Table 2). These findings were confirmed by the results of the FDA (Fig. 3).
Conclusions :
13 months of 0.01% Atropine treatment for myopia control did not affect ciliary muscle morphology. Thickness increases can be attributed to myopia progression only. Interestingly, males showed a stronger PA increase rate than females. An increase in PA on visit 1 is likely a transient effect shortly after Atropine administration. These findings were confirmed by functional data analysis of the ciliary muscle profiles. Yet, the question if CMT increase with myopia progression was slowed by Atropine remains open and might be answered by investigating further clinical parameters collected within this trial.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.