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TOPLINE:

In some children with myopia, repeated low-level red-light therapy for at least 1 year was associated with reduced cone density near the fovea and other subtle retinal abnormalities.

METHODOLOGY:

• A retrospective cohort study analyzed data from 99 Chinese children (aged 5-16 years) with myopia and compared changes in photoreceptor density — assessed using adaptive optics scanning laser ophthalmoscopy — between those who received red-light therapy and those who did not.
• Participants were recruited from January to March 2024, with inclusion criteria of spherical equivalent refraction below −6.00 diopters and best-corrected visual acuity of 20/20.
• Children in the group receiving red-light therapy (n = 52; 97 eyes; mean age, 10.3 years; 51.9% girls) underwent daily irradiation for more than 12 months; those with no history of the treatment were considered control individuals (n = 47; 74 eyes; mean age, 9.8 years; 46.8% girls).
• Participants underwent thorough ophthalmologic assessments, including testing of visual acuity and fundus photography, with measurements of axial length for density conversions from angular to metric coordinates.
• Ophthalmoscopy was used to assess cone photoreceptor density along four retinal meridians from the central fovea out to 4 degrees eccentricity; between-group differences in cell densities were evaluated.

TAKEAWAY:

• Compared with control individuals, children treated with low-level red-light exhibited a reduction in cone density, particularly within 0.5 mm of the fovea, with a mean difference of −2.1 × 10³ cells/mm² at 0.3 mm temporal eccentricity (P = .003).
• Among 10 participants, 11 eyes exhibited abnormal retinal signals — seven eyes of long-term red-light users, three eyes of short-term users, and one eye of a control individual.
• The odds of abnormal signals were higher in recipients of red-light therapy users than in control individuals (odds ratio, 7.23; 95% CI, 1.15-303.45; Fisher exact test, P = .02).
• A retinal cystoid cavity was identified in one participant in the treatment group, which was resolved by the 3-month follow-up after the therapy was discontinued.

IN PRACTICE:

Low-level red-light therapy “may exceed tissue tolerance limits, causing unexpected ganglion cell layer damage,” the authors of the study wrote. Although therapy “might control the progression of myopia, further studies are needed to provide more definitive information regarding longer-term efficacy and safety,” they added.

The new study suggests low-level red-light therapy “may have subtle effects on cone density that are not readily visualized with standard clinical tests,” wrote Jacque Duncan, MD, of the University of California San Francisco, in a commentary on the paper. This study raises questions that only may be possible to address with high-resolution retinal imaging using adaptive optics scanning laser ophthalmoscopy.

SOURCE:

This study was led by Xinyi Liao, MD, of the Peking University People’s Hospital in Beijing, China. It was published online on April 24, 2025, in JAMA Ophthalmology.

LIMITATIONS:

The retrospective design limited the ability to establish a causal relationship between low-level red-light therapy and retinal changes. This study relied on adaptive optics scanning laser ophthalmoscopy, thereby lacking comprehensive functional evaluations such as color vision assessment and microperimetry. Potential confounding factors like genetic predispositions and environmental influences were not fully controlled. Variability in the use of low-level red-light therapy devices use and adherence may have introduced bias.

DISCLOSURES:

This study was supported by the Capital’s Funds for Health Improvement and Research and the National Natural Science Foundation of China. No relevant conflicts of interest were disclosed by the authors.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.