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

## TL;DR

This study shows that orthokeratology lenses, especially those with a smaller back optical zone diameter, can significantly slow eye growth in myopic children compared to regular glasses.

## Contribution

The study demonstrates that orthokeratology lenses with a smaller back optical zone diameter provide better myopia control than larger ones or single-vision spectacle lenses.

## Key findings

- Orthokeratology lenses reduced axial elongation by 78% compared to single-vision spectacle lenses when using a 5.5 mm back optical zone diameter.
- A smaller back optical zone diameter (5.5 mm) provided 54% better myopia control than a larger diameter (6.0 mm) in orthokeratology lenses.
- Orthokeratology lenses significantly inhibited axial elongation compared to single-vision spectacle lenses over 12 months.

## Abstract

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).

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.

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).

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.