Clinical relevance: In clinical practice, 1% atropine and 1% cyclopentolate are used as cycloplegia agents to diagnose refractive error. The influence of 1% atropine on ocular biometry is obscure, and the impact of 1% cyclopentolate remains controversial.
Background: This study aims to compare the effects of atropine versus cyclopentolate cycloplegia on ocular biometry in myopic children and to determine the sites of action for atropine.
Methods: A total of 207 myopic children aged 6-12-years were included in the analysis. All participants underwent comprehensive eye examinations before and after cyclopentolate cycloplegia, after which they were randomly assigned into two groups, A and B, in a ratio of 1:1, to receive 1% or 0.01% atropine, respectively. The treatment was administered once every night for a week. Participants were re-examined one week later.
Results: Cyclopentolate cycloplegia caused a decrease in choroidal thickness (-3 ± 9 μm, p = 0.001), elongation of axial length (9 ± 16 μm, p < 0.001), loss of lens power (-0.14 ± 0.37 dioptre, p < 0.001), and a hyperopic shift (0.14 ± 0.22 dioptre, p < 0.001) in both groups. However, ocular biometry showed different changes after one-week use of 1% or 0.01% atropine (all p < 0.001). In Group A, choroid thickening (24 ± 13 μm, p < 0.001) and reduced axial length (-30 ± 27 μm, p < 0.001) were observed after atropine cycloplegia, with greater changes in lens power (0.50 ± 0.37 dioptre, p < 0.001) and spherical equivalent (0.52 ± 0.23 dioptre, p < 0.001). Group B showed a slight increase in choroidal thickness following one-week use of 0.01% atropine (6 ± 9 μm, p < 0.001), but other biometric measures showed no significant changes.
Conclusion: Cyclopentolate and atropine cycloplegia have different effects on ocular biometry. Both 1% cyclopentolate cycloplegia and 0.01% atropine resulted in choroidal thickening, indicating that the choroid may be a site of action for atropine.
Keywords: atropine; choroid; cyclopentolate; cycloplegia; myopia.