Photobiomodulation therapy retarded axial length growth in children with myopia: evidence from a 12-month randomized controlled trial evidence

Abstract

To determine whether photobiomodulation (PBM) therapy can retard ocular axial length (AL) in children with myopia. A randomized controlled clinical trial was conducted on two consecutive cohorts of 50 eligible children aged 8–12 years with ≤ − 0.75 Diopter (D) of spherical equivalent refraction (SER). Participants were randomly assigned to the intervention group (n = 25) and treated with PBM therapy or the control group (n = 25) and treated with single vision spectacles only. At the 12-month follow-up, the changes in AL and cycloplegic SER from baseline were both compared between the two groups. In addition, the subfoveal choroidal thickness (SFChT), anterior chamber depth (ACD), and central corneal refractive power (CCP) were analysed at the 3-, 6-, 9-, and 12-month follow-ups, respectively. Among the 50 children, 78% were included at the final follow-up, with a mean age of 9.7 ± 1.5 years and a mean SER of − 2.56 ± 1.70. The mean difference in AL growth between the two groups at 12 months was 0.50 mm (PBM vs. Control, − 0.02 mm ± 0.11 vs. 0.48 mm ± 0.16, P < 0.001), and the mean difference in cycloplegic SER at 12 months was + 1.25 D (PBM vs. Control, + 0.28 D ± 0.26 vs. − 0.97 D ± 0.25, P < 0.001). There were no significant differences in any of the other parameters (including SFChT, ACD, and CCP) between the two groups at any time point. PBM therapy is an effective intervention for slightly decreasing the AL to control myopia in children.Trial registration: Chinese Clinical Trial Registration Number: ChiCTR2100043619. Registered on 23/02/2021; prospectively registered. http://www.chictr.org.cn/showproj.aspx?proj=121302.

Repeated Low-level Red-light Therapy: The Next Wave in Myopia Management?

“…57 In children, short durations of daily red-light exposure slow myopia progression and axial elongation. [24][25][26][27][28][29][30][31][32][33][34] These findings collectively provide strong evidence that long-wavelength (red) light could potentially be an effective intervention for slowing myopia progression in children.…”

“…27 All these currently published trials of low-level red-light therapy are in children of Chinese descent. [24][25][26][27][28][29][30][31][32][33][34] In these trials, children were assigned to receive low-level red light on a tabletop device equipped with oculars where each eye separately viewed an internal diodeemitting long-wavelength red light. These devices were initially investigated as a potential treatment of amblyopia and have now garnered interest in myopia control.…”

“…27,34 The most commonly used instrument reports an illuminance of 1600 lux [24][25][26]28,30 and 0.29 mW of power going through a 4-mm pupil. 24,25,59 Other studies only reported power in milliwatts, which varies from 0.35 mW 33,34 to 2 mW. 29…”

“…Table 1 shows a summary of characteristics for studies comparing low-level red-light therapy with control groups. Most studies used control groups of children wearing single-vision lenses, 24,26,27,29,30,33 whereas one study used double-masked allocation, using 10% power red light in a sham device. 25 In these studies, compliance was monitored in multiple ways.…”

“…[24][25][26]28,33 Several studies noted a mean hyperopic shift in the low-level red-light cohorts. [25][26][27]29,33 Although 1% atropine has been reported to cause a short-term hyperopic shift and reduction in AL (+0.20-D spherical equivalent refraction and 0.10-mm AL reduction at 4 months), the authors are not aware of any other treatment that consistently shows a clinically meaningful initial decrease in AL. 61 Given this finding and the fact that children's AL is increasing over time naturally, Liu et al 62 hypothesized that the AL effects may be underestimated in a pediatric population.…”