Effect of orthokeratology lens wear on axial length elongation in myopic children

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.