Safety of repeated low-level red-light therapy for children with myopia

• Published in: Photodiagnosis and photodynamic therapy 2024-06, Vol.47, p.104198, Article 104198
• Main Authors: Zhu, Mengxia, Liu, Ying, Fang, Dengqin, Li, Mu, Fu, Ting, Yao, KeJun, Wang, Ping, Sun, Xufang, Xiang, Yan
• Format: Article
• Language: English
• Subjects: Child; Contrast Sensitivity - physiology; Electroretinography; Female; Humans; Low-Level Light Therapy - methods; Male; Myopia - physiopathology; Myopia - therapy; Myopia control; Photoreceptor outer segment; Repeated low-level red-light therapy; Tomography, Optical Coherence
• ISSN: 1572-1000; 1873-1597; 1873-1597
• DOI: 10.1016/j.pdpdt.2024.104198

•Repetitive low-level red-light therapy is a newly discovered effective method of myopia prevention and control.•Red light therapy is safe within 12 months and can enhance multifocal electroretinography responses.•Red light therapy increases the relative reflectance of photoreceptor outer segments which may reflect potentially detrimental effects. To investigate the safety of repetitive low-level red-light therapy (RLRLT) in children with myopia. Children with myopia were assigned to the RLRL and control groups. Axial length (AL) and spherical equivalent refraction (SER) were followed up at 3-, 6-, and 12-month. To evaluate the safety of RLRLT, at 6 and 12 months in the RLRL group, multifocal electroretinography (mfERG) and contrast sensitivity were recorded. Furthermore, optical coherence tomography was used to measure the relative reflectance of the ellipsoid zone (rEZR), photoreceptor outer segment (rPOSR), and retinal pigment epithelium (rRPER). A total of 108 children completed the trial (55 in the RLRL group and 53 in the control group). After 3, 6, and 12 months, AL was shorter and SER less myopic in the RLRL group than in the control group. Regarding the safety of the RLRLT, the response density and amplitude of the P1 wave of the first ring of the mfERG increased significantly at 6 months (P = 0.001 and P = 0.017, respectively). At 6 and 12 months, contrast sensitivity at the high spatial frequency increased. Moreover, the rEZR increased significantly at 6 months (P = 0.029), the rPOSR increased significantly at 6 and 12 months (both P < 0.001), and the increase in rPOSR was greater with greater AL regression. Based on retinal function and structure follow-up, RLRLT was safe within 12 months. However, rEZR and rPOSR increased, the effects of this phenomenon requires further observation.