Anisomyopia is a natural experimental paradigm that compares dose response between fellow eyes. This study is the first to explore whether orthokeratology (ortho-k) has a dose-response effect on axial length growth and reduces the interocular difference in axial length in anisomyopic children.
The purpose of this study was to compare the effect of ortho-k on axial length elongation between the fellow eyes of anisomyopic children.
In this retrospective study, 49 anisomyopic children who wore ortho-k lenses were assigned to the anisomyopic ortho-k group. Based on the one-to-one match principle (same age and proximate spherical equivalent), high-isomyopic and low-isomyopic groups each enrolled 49 isomyopic children who wore ortho-k lenses with spherical equivalent similar to that of the more myopic eye and the less myopic eye in the anisomyopic ortho-k group, respectively. Forty-nine anisomyopic children who wore spectacles were enrolled in the anisomyopic spectacle group. At baseline and at 1- and 2-year visits, axial length was measured. Axial length elongation and interocular difference in axial length were compared.
In the anisomyopic ortho-k group, the less myopic eyes exhibited more axial length elongation than did the more myopic eyes during 1- and 2-year treatment periods (P < .01). However, there was no significant difference in axial length elongation between the fellow eyes in the isomyopic groups and anisomyopic spectacle group. At the 2-year visit, the interocular difference in axial length of children in the anisomyopic ortho-k group significantly decreased from 0.72 ± 0.34 to 0.56 ± 0.38 mm (P < .05). In contrast, ortho-k lens–wearing isomyopic children or spectacle-wearing anisomyopic children did not show a significant change in interocular difference in axial length.
Orthokeratology could reduce the amount of anisomyopia in children primarily through stronger myopia control in the more myopic eye.
1Department of Ophthalmology, Peking University Third Hospital, Beijing Key Laboratory of Restoration of Damaged Ocular Nerve, Beijing, China *firstname.lastname@example.org
Submitted: June 18, 2017
Accepted: August 6, 2018
Funding/Support: Capital's Funds for Health Improvement and Research (2018-2-4092; to YC).
Conflict of Interest Disclosure: None of the authors have reported a financial conflict of interest.
Author Contributions: Conceptualization: YZ, YC; Data Curation: YZ; Methodology: YZ, YC; Resources: YZ; Supervision: YC; Writing – Original Draft: YZ; Writing – Review & Editing: YC.