Abstract
PURPOSE: To investigate the differences in axial elongation in myopic children wearing orthokeratology lenses (OK lenses) with different back optical zone diameters (BOZD) and single-vision spectacle lenses (SVL). MATERIALS AND METHODS: This study was a retrospective cohort study that included a total of 230 myopic children aged 8-12 years with spherical equivalent ranging from -5.00 D to -0.50 D, who had been wearing lenses continuously for at least 1 year. The OK lens group consisted of 162 participants, including 86 individuals wearing lenses with a 6.0 mm BOZD (6.0 group) and 76 individuals wearing lenses with a 5.5 mm BOZD (5.5 group). The SVL group included 68 participants. The differences in axial elongation after 12 months of lens wearing were compared among the groups. RESULTS: After 12 months of lens wear, significant differences were found in axial elongation between the 5.5 group/6.0 group and SVL group (p < 0.001). Compared to the SVL group, the median axial elongation was significantly reduced by 78% in the 5.5 group (0.295 vs. 0.065 mm, p < 0.001) and by 53% in the 6.0 group (0.295 vs. 0.140 mm, p < 0.001). In addition, among patients wearing OK lenses, the axial elongation in the 5.5 group was significantly decreased by 54% compared to the 6.0 group after 12 months of lens wear (p < 0.001). CONCLUSION: Wearing OK lenses could effectively inhibit axial elongation in myopic children compared to wearing SVL, with better myopia control achieved by using OK lenses with a smaller BOZD.