Short‐term effects of cyclopentolate and tropicamide eye drops on macular choroidal thickness in myopic children

Abstract

AbstractBackgroundTo investigate the short‐term effects of cyclopentolate and tropicamide eyedrops on choroidal thickness (ChT) in myopic children using placebo or low‐dose atropine eyedrops.MethodsThe analysis included 242 myopic individuals (7–19 years) enrolled in two randomised placebo‐controlled clinical trials of low‐dose atropine eyedrops. Cycloplegia was induced using either one drop of 1% cyclopentolate (n = 161), two drops of 1% cyclopentolate (n = 32) or two drops of 1% tropicamide (n = 49). ChT measurements were taken using swept‐source optical coherence tomography before and 30 min after administering the cycloplegic eye drops. A subset of 51 participants underwent test–retest measurements prior to cycloplegia.ResultsMean changes in subfoveal ChT after two drops of tropicamide and one and two drops of cyclopentolate were −2.5 μm (p = 0.10), −4.3 μm (p < 0.001) and −9.6 μm (p < 0.001), respectively. Subfoveal ChT changes after one and two drops of cyclopentolate were significantly greater than the test–retest changes (test–retest mean change: −3.1 μm; p < 0.05), while the tropicamide group was not significantly different (p = 0.64). Choroidal thinning post‐cyclopentolate was not significantly different between atropine and placebo treatment groups (p > 0.05 for all macular locations). The coefficient of repeatability (CoR) in the tropicamide group (range: 8.2–14.4 μm) was similar to test–retest (range: 7.5–12.2 μm), whereas greater CoR values were observed in the cyclopentolate groups (one drop: range: 10.8–15.3 μm; two drops: range: 12.2–24.6 μm).ConclusionsCyclopentolate eye drops caused dose‐dependent choroidal thinning and increased variation in pre‐ to post‐cycloplegia measurements compared with test–retest variability, whereas tropicamide did not. These findings have practical implications for ChT measurements when cyclopentolate is used, particularly for successive measurements.