Purpose. To investigate the influences of atropine on changes in anterior segment geometry, as measured by ultrasound biomicroscopy in children. Methods. A prospective observational study was performed. Anterior segment parameters were obtained by UBM before and after the instillation of 1% atropine. Univariate linear regression was performed to identify the variables contributing to the changes in the trabecular meshwork-iris angle (TIA). Results. The study included 21 boys and 37 girls with a mean age of 10.79 ± 2.53 years. Anterior chamber parameters including the central anterior chamber depth, TIA, angle opening distance at 500 μm from the scleral spur, iris thickness 750 μm and 1500 μm from the scleral spur, trabecular-ciliary angle (TCA), trabecular-ciliary process distance, sclera-iris angle (SIA), and sclera-ciliary process angle significantly increased after cycloplegia ( P < 0.05 ). In contrast, the lens vault, iris cross-sectional area, and maximum ciliary muscle thickness significantly decreased after cycloplegia. Univariate analysis identified the change in TCA and the change in SIA and the TIA before mydriasis as determinants of the change in TIA. Conclusions. Atropine causes statistically significant changes in various anterior segment parameters in children. The change in anterior chamber angle is associated with the change in TCA and the change in SIA and the TIA before mydriasis.

Introduction: To assess changes of choroidal thickness (ChT) after administration of 1% atropine for 1 week in myopia, emmetropia, and hyperopia children. Methods: A total of 235 children aged 4–8 years, which included 46 myopia, 34 emmetropia, and 155 hyperopia patients were recruited and divided into three groups according to the spherical equivalent with the use of 1% atropine twice a day for 1 week. The ChT was measured at baseline and 1 week. Results: In the myopia and emmetropia groups, following administration of 1% atropine gel, the ChT thickened significantly under the fovea (i.e., from 278.29 ± 53.01 μm to 308.24 ± 57.3 μm, P < 0.05; from 336.10 ± 78.60 μm to 353.46 ± 70.22 μm, P < 0.05, respectively) and at all intervals from the fovea, while in the hyperopia group, there was no significant difference in the ChT except the nasal side (P < 0.05) . Conclusion: Topical administration of 1% atropine gel for 1 week significantly increased the subfoveal and parafoveal ChT in children with myopia and emmetropia. Atropine did not increase the ChT in hyperopia children, except at the nasal side.