Effects of repeated low-level red-light therapy on macular retinal thickness and microvascular system in children with myopia

OBJECTIVE: The objective of the study was to use optical coherence tomography angiography (OCTA) to analyze the effects of repeated low-level red-light (LLLT) therapy on macular retinal thickness and the microvascular system in children with myopia to evaluate the safety of this therapy. METHODS: This prospective study included 40 school-age children with myopia (80 eyes), aged 7-14 years, who received therapy using a LLLT instrument. At baseline and therapy for 1 month, 3 months, 6 months, all children underwent comprehensive ophthalmological examinations, including slit-lamp examination, uncorrected visual acuity, best-corrected visual acuity, spherical equivalent degree, axial length, and OCTA. The vessel densities of the superficial retinal capillary plexus, macular inner retinal thickness, and full-layer retinal thickness were measured. RESULTS: The macular inner retinal thickness increased at 1 month and remained unchanged thereafter, It differed significantly in nine areas at 1, 3, and 6 months compared to the thicknesses before therapy (P < 0.05); however, we observed no significant differences between the different time points (P > 0.05). The macular full-layer retinal thickness increased at 1 month and remained unchanged thereafter; the changes showed significant differences at 1 month and 3 months compared to before therapy, for the inner nasal region (P < 0.05). The other eight areas showed significant differences at 1, 3, and 6 months compared with before therapy (P < 0.05); however, no significant difference was observed between the different time points after therapy (P > 0.05). The vessel density of the superficial retinal capillary plexus did not differ significantly among the four groups (P > 0.05). CONCLUSIONS: LLLT therapy was safe. The school-aged children exhibited macular thickening after LLLT therapy, which had no significant effect on macular microcirculation.