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

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. 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. 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). LLLT therapy was safe. The school-aged children exhibited macular thickening after LLLT therapy, which had no significant effect on macular microcirculation.