Red light therapy for myopia: what the evidence shows, and the safety question

Repeated low-level red-light (RLRL) therapy asks a child to look into a desktop device that emits 650 nm red light for three minutes, twice a day. It has produced some of the largest treatment effects reported in a myopia trial, and some of the most serious safety questions. Both deserve to be set out plainly.

What the evidence shows

Efficacy. In a multicentre randomised trial in China, 264 children were assigned to RLRL plus single-vision spectacles or spectacles alone. After 12 months, axial length had grown 0.13 mm with RLRL against 0.38 mm without, and myopia progressed by 0.20 D against 0.79 D. No severe adverse events or structural damage on OCT were recorded in the trial (Jiang et al., 2022).

Choroid. In the same trial, macular choroidal thickness increased in treated children and thinned in controls, and the three-month change predicted 12-month myopia control (Xiong et al., 2023).

Combination. In a small randomised trial of children whose eyes were still elongating quickly in orthokeratology, adding RLRL gave a 12-month axial length change of -0.02 mm against 0.27 mm with orthokeratology alone (Xiong et al., 2024).

The safety question

• A case report in JAMA Ophthalmology described retinal damage after repeated low-level red-light exposure (Liu et al., 2023).
• An independent laboratory study measured two commercial RLRL devices and found that three minutes of continuous viewing approached or exceeded the maximum permissible exposure under laser safety standards. The authors advised caution until safety standards can be confirmed (Ostrin and Schill, 2024).

An honest read of the evidence

The efficacy signal is strong but comes almost entirely from Chinese cohorts over one to two years, with treatment that is hard to mask. The mechanism is not established, and what happens after stopping is not settled. Long-term retinal safety in children is unproven. On current evidence RLRL belongs in properly monitored research, with retinal imaging and functional testing, rather than in routine practice. NZERC authors have published on red-light therapy in myopia management in Clinical & Experimental Optometry (Wood, Dykgraaf and Lallu, 2026).

Myopia device research at NZERC

Light-based myopia treatments need independent safety and efficacy data with careful retinal monitoring. The New Zealand Eye Research Centre (NZERC) has OCT, axial length and choroidal thickness and vascularity measurement on site. Device manufacturers and sponsors are invited to read our information for sponsors and CROs and our guide to pilot studies in New Zealand. Families can register their interest in myopia studies.

References

• Jiang Y, et al. Effect of repeated low-level red-light therapy for myopia control in children: a multicenter randomized controlled trial. Ophthalmology 2022;129(5):509-519. doi:10.1016/j.ophtha.2021.11.023
• Xiong R, et al. Longitudinal changes and predictive value of choroidal thickness for myopia control after repeated low-level red-light therapy. Ophthalmology 2023;130(3):286-296. doi:10.1016/j.ophtha.2022.10.002
• Xiong R, et al. Myopia control effect of repeated low-level red-light therapy combined with orthokeratology: a multicenter randomized controlled trial. Ophthalmology 2024;131(11):1304-1313. doi:10.1016/j.ophtha.2024.05.015
• Liu H, Yang Y, Guo J, Peng J, Zhao P. Retinal damage after repeated low-level red-light laser exposure. JAMA Ophthalmol 2023;141(7):693-695. doi:10.1001/jamaophthalmol.2023.1548
• Ostrin LA, Schill AW. Red light instruments for myopia exceed safety limits. Ophthalmic Physiol Opt 2024;44(2):241-248. doi:10.1111/opo.13272