A multicenter randomized clinical trial demonstrated the efficacy and safety of repeated low-level red-light therapy in controlling high myopia in children and adolescents. The study, conducted between February 2021 and April 2023, assessed 192 participants aged 6 to 16 years with high myopia, defined as:
- cycloplegic spherical equivalent refraction (SER) of at least -4.0 diopters
- astigmatism at least 2.0 diopters
- anisometropia of at least 3.0 diopters
- best-corrected visual acuity of 0.2 logarithm of the minimum angle of resolution or better
“High myopia not only impairs visual acuity but also substantially raises the risk of sight-threatening complications such as myopic macular degeneration, glaucoma, or retinal detachment,” investigators explained in an article published in AAO.
They further described the current treatment gap in high myopia: It is often out of range for orthokeratology, and the efficacy of low-concentration atropine or defocus glasses has not been proven in high myopic cases, though both treatments have demonstrated efficacy for low or moderate myopia.
Repeated low-level red light (RLRL) therapy continues to be evaluated as a possible way to fill this gap. Previous studies found efficacy “among individuals with a higher degree of myopia, and a significant proportion of children experienced substantial axial shortening after treatment.”
Participants in this study were randomly assigned to receive either RLRL therapy combined with single-vision spectacles (intervention group) or single-vision spectacles alone (control group). The RLRL therapy used a portable desktop device that emitted low-level red light for 3 minutes per session, twice daily, with a minimum interval of 4 hours, 7 days a week. The primary outcome measure was the change in axial length (AL) at the 12-month follow-up, while the key secondary outcome was the change in cycloplegic SER.
Out of the 192 randomized participants, 188 completed the study (96 in the RLRL group and 92 in the control group). After 12 months, the adjusted mean change in AL was -0.06 mm in the RLRL group compared to 0.34 mm in the control group, with a mean difference of 0.41 mm. Additionally, 53.3% of participants in the RLRL group experienced substantial axial shortening (> 0.05 mm). The mean change in SER was 0.11 D in the RLRL group versus -0.75 D in the control group, with a mean difference of -0.86 D.
The study reported no severe adverse events, except for one case of conjunctivitis in the intervention group. The RLRL therapy was well-tolerated, with no significant differences in intraocular pressure or structural damage. The intervention group demonstrated an 84% median treatment compliance rate.
“Repeated low-level red light demonstrates much stronger treatment efficacy among high myopia in children and adolescents,” effectively reducing axial length and slowing myopia progression. Still, the researchers noted that continued study is needed, especially regarding safety. They also encouraged future research to study whether treatment effects are maintained after red light therapy.
A full list of author disclosures can be found in the published research
