Abstract
Purpose :
This project aimed to examine the persistence of atropine’s effect upon choroidal thickness and its interaction with hyperopic blur in a population of young adult myopes.
Methods :
Twenty young (age 18-35 years) healthy participants, with myopic, spherical equivalent refractive errors of – 0.75 to -6.00 D (mean ± SD -2.85 ± 1.64 D), participated in this study. Subfoveal choroidal thickness (SFCT) measurements were derived from scans collected with a SD-OCT instrument (Copernicus SOCT-HR) prior to, as well as 30 and 60 minutes following the introduction of three testing conditions: (1) placebo (0.3% hydroxypropyl methylcellulose)/monocular hyperopic (-3 D) blur, (2) placebo/monocular hyperopic blur one day after administration of 0.01% atropine, and (3) placebo/no blur. All measurements were carried out on the right eye only. Each combination of blur and pharmacological agent was tested on a separate day at approximately the same time of day (within a range of 25 mins).
Results :
Repeated measures ANOVA revealed significant main effects of the condition and time on the change in SFCT from baseline, and a significant interaction between the condition and time (all p<0.001). Eyes exposed to hyperopic blur and placebo developed a small and statistically significant decrease in SFCT (mean change: -6 ± 1 μm, p = 0.008, and -11 ± 2 μm, p = 0.0001 after 30 and 60 minutes respectively), whereas administration of 0.01% atropine one day before the introduction of hyperopic blur inhibited the thinning of the choroid (mean change of -1 ± 2 μm and +1 ± 4 µm after 30 and 60 minutes respectively) compared to baseline (both, p > 0.05). There was no significant difference between the baseline SFCT measurements (prior to blur or pharmacological agent) for any of the conditions tested with mean baseline choroidal thickness of 292 ± 8 μm (placebo/hyperopic blur), 296 ± 8 μm (placebo/hyperopic blur one day after administration of 0.01% atropine) and 293 ± 9 μm (placebo/no blur).
Conclusions :
Hyperopic blur leads to significant short-term thinning of the choroid. Low dose atropine appears to inhibit signals associated with hyperopic defocus that cause thinning of the choroid for at least 24 hours after initial instillation, even though the baseline sub-foveal choroidal thickness was unchanged.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.