Abstract: Objective To assess the clinical effectiveness and safety of utilizing a 650-nm low-level red light in combination with orthokeratology for correcting and retarding myopia. Methods A total of 71 patients with myopia aged ≥7 years were carefully selected and categorized into four distinct groups based on their individual condition: patients wearing single-vision spectacles(control group), patients receiving 650-nm low-level red light treatment and wearing single-vision spectacles(red-light group), patients wearing orthokeratology lenses(OK group), and patients receiving 650-nm low-level red light treatment and wearing with orthokeratology lenses(combination group). Follow-up examinations were carried out at 1-, 3-, and 6-month intervals following enrollment to assess various parameters, including axial length, spherical equivalent, choroid thickness, best-corrected visual acuity and intraocular pressure. The safety of the procedure was evaluated using optical coherence tomography to observe retinal structures within a 6-mm range of the macular fovea. Two-factor analysis of variance, χ2 test, and repeated-measures analysis of variance were used to analyze the data. Results At 6 months, the change of axial length relative to the baseline period value difference in the control group, OK group, red-light group and combination group were significant［(0.181±0.104)mm、(0.069±0.108)mm、(-0.130±0.141)mm、(-0.164±0.118)mm, P<0.001］. The combination group exhibited the most effective control over the axial length. Additionally, red-light group and control group in the change of equivalent spherical refractive error relative to the baseline period value difference was significant ［(0.028±0.274)D、(-0.309±0.193)D, P<0.001］. The change in choroidal thickness relative to the baseline period value difference in the red-light, OK, and combination groups at 1, 3, and 6 months were also significant(all P<0.001). Only the combination group showed a continuous growth trend for 6 months. The retinal structures of both the red-light and combination groups displayed clarity within a 6-mm range of the macular fovea, and no abnormalities were detected. Conclusion The application of 650-nm low-level red-light in combination with an orthokeratology lens can regulate the progression of myopia. Furthermore, the efficacy of the combination of these two methods surpasses that of either red light or the orthokeratology lens used individually, and did not affect the structure of retina and best corrected visual acuity.

Key words: Myopia, 650-nm low-level red light, Orthokeratology, Axial length, Choroidal thickness