Effect of Repeated Low-level Red Light on Myopia Prevention Among Children in China With Premyopia

Abstract

ImportanceMyopia is a global concern, but effective prevention measures remain limited. Premyopia is a refractive state in which children are at higher risk of myopia, meriting preventive interventions.ObjectiveTo assess the efficacy and safety of a repeated low-level red-light (RLRL) intervention in preventing incident myopia among children with premyopia.Design, Setting, and ParticipantsThis was a 12-month, parallel-group, school-based randomized clinical trial conducted in 10 primary schools in Shanghai, China. A total of 139 children with premyopia (defined as cycloplegic spherical equivalence refraction [SER] of −0.50 to 0.50 diopter [D] in the more myopic eye and having at least 1 parent with SER ≤−3.00 D) in grades 1 to 4 were enrolled between April 1, 2021, and June 30, 2021; the trial was completed August 31, 2022.InterventionsChildren were randomly assigned to 2 groups after grade stratification. Children in the intervention group received RLRL therapy twice per day, 5 days per week, with each session lasting 3 minutes. The intervention was conducted at school during semesters and at home during winter and summer vacations. Children in the control group continued usual activities.Main Outcomes and MeasuresThe primary outcome was the 12-month incidence rate of myopia (defined as SER ≤−0.50 D). Secondary outcomes included the changes in SER, axial length, vision function, and optical coherence tomography scan results over 12 months. Data from the more myopic eyes were analyzed. Outcomes were analyzed by means of an intention-to-treat method and per-protocol method. The intention-to-treat analysis included participants in both groups at baseline, while the per-protocol analysis included participants in the control group and those in the intervention group who were able to continue the intervention without interruption by the COVID-19 pandemic.ResultsThere were 139 children (mean [SD] age, 8.3 [1.1] years; 71 boys [51.1%]) in the intervention group and 139 children (mean [SD] age, 8.3 [1.1] years; 68 boys [48.9%]) in the control group. The 12-month incidence of myopia was 40.8% (49 of 120) in the intervention group and 61.3% (68 of 111) in the control group, a relative 33.4% reduction in incidence. For children in the intervention group who did not have treatment interruption secondary to the COVID-19 pandemic, the incidence was 28.1% (9 of 32), a relative 54.1% reduction in incidence. The RLRL intervention significantly reduced the myopic shifts in terms of axial length and SER compared with the control group (mean [SD] axial length, 0.30 [0.27] mm vs 0.47 [0.25] mm; difference, 0.17 mm [95% CI, 0.11-0.23 mm]; mean [SD] SER, –0.35 [0.54] D vs –0.76 [0.60] D; difference, –0.41 D [95% CI, –0.56 to –0.26 D]). No visual acuity or structural damage was noted on optical coherence tomography scans in the intervention group.Conclusions and RelevanceIn this randomized clinical trial, RLRL therapy was a novel and effective intervention for myopia prevention, with good user acceptability and up to 54.1% reduction in incident myopia within 12 months among children with premyopia.Trial RegistrationClinicalTrials.gov Identifier: NCT04825769

Daily Low-Level Red Light for Spherical Equivalent Error and Axial Length in Children With Myopia

“…Two recent studies explored the possibility of using atropine for myopia prevention and reported opposite findings. For 650-nm LLRL, a clinical trial reported a 54.1% reduction in incident myopia among children with premyopia within 12 months . In our study, the 1-year myopia incidences were 7.1% and 23.2% for the LLRL and control groups, respectively, which was a 69.4% reduction.…”

“…For 650-nm LLRL, a clinical trial reported a 54.1% reduction in incident myopia among children with premyopia within 12 months. 49 In our study, the 1-year myopia incidences were 7.1% and 23.2% for the LLRL and control groups, respectively, which was a 69.4% reduction. For children without myopia but at high risk of myopia (eg, when the SER progresses more than −0.75 D per year), the 650-nm LLRL can be a potential treatment option; however, further ethical exploration is needed in this regard.…”

“…The 650-nm LLRL may be a preventive measure for myopia. Previously, few studies [47][48][49] on myopia prevention were conducted because of ethical debates. Two recent studies 47,48 explored the possibility of using atropine for myopia prevention and reported opposite findings.…”

Red light instruments for myopia exceed safety limits

“…In animal studies, the duration of red light exposure was generally for the entire waking period (12-14 h per day), while protocols in children use 3 min of red light exposure twice a day. Since 2021, over 24 papers have been published on red light therapy for myopia, [2][3][4][5][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] including three review papers. [27][28][29] Eyerising International, manufacturer of the Eyerising Myopia Management Device, advertises the instrument for use in children as young as 3 years old, with online claims that over 100,000 children have been or are currently being treated.…”

Assessing the rebound phenomenon in different myopia control treatments: A systematic review

“…20 Although the mechanism of action is not fully understood, this device emits a red light (650 nm) that seems to improve scleral hypoxia and thus prevent myopia progression. 20,60 RCTs evaluating myopia control with this treatment are limited. Chen et al 34 and Xiong et al 33 reported the highest rebound effect after LLLT cessation compared with the other myopia control treatments included in this systematic review.…”