Repeated low-level red-light therapy could be associated with reduced myopia progression in pediatric patients over a period of 12 months, with treatment effects increasing over time, according to a systematic review and meta-analysis.
At 12 months, pooled results showed improvements of 0.68 diopters in spherical equivalent refraction, a reduction of 0.30 mm in axial length, and an increase of nearly 27 µm in choroidal thickness compared with controls.
Study Design and Methods
In the study, investigators conducted a systematic search of PubMed, Embase, and the Cochrane Library through August 2025 for randomized controlled trials evaluating repeated low-level red-light therapy in patients younger than 18 years with myopia or premyopia.
A total of 28 randomized controlled trials involving 3,573 pediatric patients met inclusion criteria. The primary outcome was change in spherical equivalent refraction. Secondary outcomes included axial length, choroidal thickness, anterior chamber depth, central corneal thickness, lens thickness, and uncorrected visual acuity.
Across most of the trials, treatment consisted of red light at a wavelength of approximately 650 nm delivered for 3 minutes per session, twice daily, 5 or 7 days per week.
Duration-Dependent Efficacy
Treatment effects increased with longer follow-up:
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At 6 months, spherical equivalent refraction improved by 0.36 diopters vs control
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At 12 months, improvement increased to 0.68 diopters.
Axial length and choroidal thickness showed similar patterns, with greater effects observed over time.
Subgroup analyses showed that treatment response varied by baseline refractive error. At 12 months:
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Premyopia: 0.42-diopter improvement
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Moderate myopia: 0.69-diopter improvement
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High myopia: 0.90-diopter improvement.
The patients with higher baseline myopia experienced the greatest benefit.
A separate analysis found no statistically significant differences between 5-day and 7-day weekly treatment regimens.
Safety and Structural Outcomes
Short-term structural parameters—including anterior chamber depth, central corneal thickness, and lens thickness—remained stable over 6 and 12 months, and no severe treatment-related adverse events were reported.
However, some patients discontinued treatment as a result of persistent afterimages or discomfort from brightness. Reported adverse effects included transient visual disturbances, photophobia, dry eye, and, in some studies, corneal staining or conjunctival inflammation.
Uncorrected visual acuity outcomes favored treatment. Patients receiving therapy were more likely to achieve greater than 2-line improvement and less likely to have greater than 2-line worsening compared with control.
Retinal Safety Considerations
The investigators noted that retinal structural outcomes were inconsistently reported and could not be quantitatively analyzed.
They also cited emerging external evidence suggesting potential retinal effects with prolonged use beyond 1 year, including laboratory modeling of light exposure limits and observational data showing reduced cone density in a small cohort. These findings didn't establish causality but highlight the need for further investigation.
Certainty of Evidence
Using the GRADE framework:
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Evidence for spherical equivalent refraction and choroidal thickness improvements was rated moderate certainty.
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Evidence for axial length reduction was rated low certainty because of inconsistency and potential publication bias.
Limitations
All but one trial were conducted in China, which may have limited generalizability. Follow-up was limited to 12 months, leaving long-term efficacy, posttreatment effects, and cumulative safety unclear.
The analysis also didn't directly compare red-light therapy with other interventions such as atropine or orthokeratology.
Conclusion
Repeated low-level red-light therapy was associated with slowed myopia progression in pediatric patients, with increasing benefit over time and stable short-term structural findings.
“Longer-term trials incorporating comprehensive retinal safety assessment are required,” concluded lead study author Lee-Yuan Lin, of the Taipei Medical University School of Medicine, and colleagues.
The study authors reported no conflicts of interest.
