Changes in the thickness of the crystalline lens components before and after cycloplegia in children with different refractive errors.

Objective: To evaluate changes in the thickness of the crystalline lens components in children with different refractive errors before and after cycloplegia.

Methods: This prospective study recruited 132 right eyes from 132 children (age 5-15 years) with different spherical equivalent (SE) ranging from -6.00 diopters (D) to +6.75 D. We categorized these eyes into non-myopia (N = 30), low-myopia (N = 77), and moderate-myopia (N = 25) groups. The thickness parameters of the crystalline lens components, including lens thickness (LT), lens nucleus thickness (LNT), anterior cortex thickness (ACT), and posterior cortex thickness (PCT), were assessed using optical coherence tomography before and after 0.5 % tropicamide-induced cycloplegia.

Results: After cycloplegia, LT significantly decreased from 3.47 ± 0.20 to 3.41 ± 0.20 mm in non-myopia eyes (P < 0.05), and from 3.30 ± 0.17 to 3.27 ± 0.16 mm in low-myopia eyes (P < 0.05), with no significant changes in moderate-myopia eyes (P < 0.05). LNT decreased from 3.15 ± 0.19 to 3.09 ± 0.19 mm in non-myopia eyes (P < 0.05), and from 3.02 ± 0.20 to 2.99 ± 0.17 mm in low-myopia eyes (P < 0.01), with no reduction observed in moderate-myopia eyes (P > 0.05). Cycloplegia-induced changes in ACT and PCT (all P > 0.05) did not differ significantly between the groups. SE was positively correlated with LT and LNT before (Pearson's r = 0.353 and 0.272, respectively; both P < 0.05) and after cycloplegia (r = 0.285 and 0.198, respectively; both P < 0.05).

Conclusions: LT and LNT significantly decreased after cycloplegia induced by 0.5 % tropicamide in children with non-myopia and low-myopia, while neither ACT nor PCT changed significantly. SE was positively correlated with LT and LNT.