Low‐intensity, long‐wavelength red light slows the progression of myopia in children: an Eastern China‐based cohort

Abstract

Myopia is prevalent worldwide, particularly in East and Southeast Asia. Recent studies have suggested that the spectral composition of ambient lighting in uences refractive development, especially in humans. We aimed to determine the effect of 650-nm single-wavelength red light on the inhibition of myopia progression in children. In this retrospective cohort study, 105 myopic children (spherical equivalent refractive error [SER], -6.75 to -1.00 dioptres (D)) aged from 4 to 14 years old were retrospectively reviewed. Subjects were treated with 650-nm, low-intensity, single-wavelength red light twice a day for 3 minutes each session, with at least a 4-hour interval between sessions. IOL Master was utilized to measure the axial length (AL) and corneal curvature. Choroidal images were assessed using enhanced depth imaging optical coherence tomography (EDI-OCT), and the luminal area (LA) and stromal area were converted to binary images by the Niblack method. At baseline, the mean SER was -3.09 ± 1.74 D and -2.87 ± 1.89 D at 9 months, and signi cant changes occurred over time (P = 0.019). The AL increased by -0.06 ± 0.19 mm for 9 months (0.21 ± 0.15 mm pretreatment; P 0.001). The subfoveal choroidal thickness (SFChT) had changed by 45.32 ± 30.88 μm at the 9-month examination (P 0.001).Repetitive exposure to 650-nm, low-intensity, single-wavelength red light effectively slowed the progression of myopia and reduced axial growth after short treatment durations. These results require further validation in a longitudinal study, as well as further research in animal models.

Efficacy Comparison of Repeated Low-Level Red Light and Low-Dose Atropine for Myopia Control: A Randomized Controlled Trial

“… 16 – 18 This study result aligns with previous findings, with AL changes of −0.01 mm at 6 months and 0.08 mm at 1 year in the RLRL group. Refraction changes were also similar, with SER changes of 0.29 D at 6 months and 0.05 D at 6 to 12 months, similar to the results for the studies by Jiang et al 16 (−0.03 D and 0.20 D, respectively) and Zhou et al 17 (0.19 D at 6 months). The continuity of such promising results reinforces the notion that RLRL is an effective treatment for AL and refraction in myopes.…”

“… 16 A similar effect was observed after a 9-month follow-up in a retrospective study. 17 When Xiong et al 18 compared RLRL with orthokeratology, a more profound effect on axial length (AL) control was evident after RLRL treatment for 6 months. In these studies, a 650-nm, single-wavelength red light was used, and the protective effect appears to be associated with an increase in choroidal thickness.…”

Seasonal Variation in Diurnal Rhythms of the Human Eye: Implications for Continuing Ocular Growth in Adolescents and Young Adults

“…Five had increases in AL that were compatible with coordinated growth (0.023 mm ≤ ΔAL ≤ 0.052 mm) ( Table 6 , participants 2–6), and one presented with annual AL shortening (ΔAL = −0.062). The decrease in AL in either season observed in some participants and throughout the year for this one participant could be indicative of axial elongation being reversible—as previously reported in animals 67 and humans (children, 68 – 72 as well as adolescents and young adults 13 , 31 , 73 , 74 ). Nonetheless, as reported from animal studies, 67 the amount of choroidal thickening does not equal the amount of eye shortening.…”

Light Signaling and Myopia Development: A Review

“…The 630 nm light used by Hung et al [ 117 ] and the 624 ± 10 nm light used by Gawne et al [ 118 ] showed significant effects on myopia control in rhesus monkeys and tree shrews. Recently, He et al found that repeated low-level red light (RLRL) therapy (650 nm, 1600 lx) could effectively improve the progression of myopia in children aged 8–13 years [ 119 ], and low-intensity, long-wavelength red light therapy (LLRT, 635 nm) inhibited myopia progression in children in an Eastern China-based cohort [ 120 ]. The effect of red light on myopia has recently gained more attention (Table 1 ).…”