Effect of orthokeratology on axial length elongation in moderate myopic and fellow high myopic eyes of children

The effects of orthokeratology (Ortho-K) on myopic eyes was examined, providing confidence to optometrists applying Ortho-K to high myopic and anisometropic children. Ortho-K slows the progression of low to moderate myopia. The effectiveness of Ortho-K in Chinese children with fellow moderate and high myopic eyes was determined. This retrospective study included female (n = 35) and male (n = 30) children with moderate myopia in one eye (spherical equivalent refractive (SER) error ≤ -3.00 D, but > -6.00 D) and high myopia in the contralateral eye (SER error ≤ -6.00 D). Three age groups were included: 7-10-years (n = 18), 11-12-years (n = 21), and 13-15-years (n = 26). Baseline refraction and axial lengths were measured before fitting Ortho-K lenses worn nightly for at least eight-hours, and after one-year. Axial length increased 0.14 ± 0.13-mm (mean ± standard deviation) and 0.13 ± 0.16-mm in the moderate and high myopic groups respectively (p = 0.78). For females, axial elongation in the moderate and high myopic groups was 0.10 and 0.08-mm respectively. For males, it was 0.19-mm in both groups. Axial elongation in 7-10-year-old children with moderate and high myopic eyes was 0.24 ± 0.14 and 0.21 ± 0.15-mm respectively. In 11-12-year-old children, it was 0.12-mm in both myopic groups. In 13-15-year-old children, it was 0.09-mm in both groups. In moderate myopic eyes, axial elongation in the youngest group was greater than the other two age groups (p