The effect of orthokeratology on axial length elongation in children with myopia: Contralateral comparison study.

Purpose: To evaluate the effectiveness of the orthokeratology (OK) lens slowing myopic progression compared with no intervention in pediatric eyes METHODS: A retrospective review of medical records was performed on 45 monocular myopic subjects 7 to 13 years of age who were treated with monocular ortho-k lens and followed-up for more than 12 months. The monocular myopia in the subjects' eyes was -0.75 to -4.25 D (diopter), and near emmetropia in the contralateral and with-the-rule astigmatism no greater than -1.50 D. Axial elongation OU, reflecting the progression of myopia was measured at baseline using the same AL-Scan Optical Biometer and compared between the two eyes of each individual every six months for one year in all subjects and for two years in 9 subjects.

Results: After 12 months of lens wear, axial length had increased by 0.36 ± 0.23mm in the control eyes (P < 0.001) but showed far less change (+0.07 ± 0.21 mm) in the OK eyes (P = 0.038). The nine subjects followed-up for 2 years showed no axial length change (+0.16 ± 0.25 mm) in the OK eyes (P = 0.095) after 24 months and significant axial length growth (+0.38 ± 0.26 mm; P = 0.002) in the control eyes. Control eyes showed progressive axial length growth throughout the study compared with the one OK lens eye.

Conclusions: Using a contralateral eye study design, which prevented the influence of potential confounding factors, Effectiveness of the OK lens was proved. Myopic progression within a subject was excellent compared with no intervention.