Controlling anisomyopia in children by orthokeratology: A one-year randomised clinical trial

Purpose: To investigate the effects of overnight orthokeratology (OK) lenses wear on the interocular axial length (AL) difference in anisomyopic children.Methods: Sixty anisomyopic children (8-14 years old) were enrolled in this one-year prospective, randomised controlled study. Subjects were randomly assigned to wear OK lenses (OK group) or single-vision spectacles (control group). AL was monitored at baseline and every six months using an IOL Master biometer, and axial elongation and interocular AL differences were compared between the groups. Results: In the control group, the more myopic eyes had similar axial elongation (0.36 +/- 0.17 mm) to the less myopic eyes (0.37 +/- 0.17 mm) at the one-year follow-up (P > 0.05). In the OK group, the less myopic eyes exhibited significantly greater axial elongation (0.24 +/- 0.17 mm) than the more myopic eyes (0.13 +/- 0.13 mm) at the one-year follow-up (P < 0.05). The mean interocular AL difference significantly decreased in the OK group over one year, from 0.47 +/- 0.24 mm to 0.35 +/- 0.22 mm (P < 0.05). However, the mean interocular AL difference decreased only slightly in the control group, from 0.56 +/- 0.28 mm to 0.55 +/- 0.28 mm (P > 0.05).Conclusion: This randomised, controlled study demonstrated that OK reduces the interocular AL difference in anisomyopic children due to stronger myopic control of the more myopic eye.