Six-month repeated irradiation of 650 nm low-level red light reduces the risk of myopia in children: a randomized controlled trial.

PURPOSE: To evaluate whether the six-month repeated irradiation of 650 nm low-level red light (LLRL) decreases the risk of myopia onset in children. METHODS: This was a single-masked, randomized controlled trial. A total of 112 children (aged 6-12 years) were enrolled and randomized to the treatment group or control group in a 1:1 ratio. The cycloplegic spherical equivalent error (SER) of children at baseline was -0.5 diopter (D) to 3D. Children in the treatment group were irradiated with the 650 nm LLRL for 6 min daily. No intervention was given to the control. The primary outcomes are myopia incidence, change in cycloplegic SER, and change in axial length (AL). RESULTS: For the treatment group and control group, the six-month myopia incidence rates were 1.8% (95% confidence interval, CI: 0.2-4.9%) and 12.5% (95% CI: 5.5-21.9%), respectively. The difference was significant (p = 0.028). The median changes in AL for the treatment group and control group were -0.02 (interquartile range, IQR: -0.12 to 0.06) mm, and 0.09 (IQR: 0-0.18) mm, respectively. The difference was significant (p < 0.001). The median changes in cycloplegic SER for the treatment group and control group were 0 (IQR: 0-0.25) D, and -0.125 (IQR: -0.375 to 0) D, respectively. The difference was significant (p < 0.001). There was no adverse event. CONCLUSION: The repeated irradiation of 650 nm LLRL may have a strong effect for myopia prevention in children, without risk of adverse events. TRIAL REGISTRATION: this trial is retrospectively registered in the Chinese Clinical Trial Registry ( http://www.chictr.org.cn/ ), the registration number is ChiCTR2200058963.

Investigation of the Efficacy and Safety of 650 nm Low-Level Red Light for Myopia Control in Children: A Randomized Controlled Trial.

INTRODUCTION: To evaluate the 6-month efficacy and safety of 650 nm low-level red light (LLRL) for myopia control in children. METHODS: This was a single-center, single-masked randomized controlled trial. A total of 224 children aged 6-12 years with spherical equivalent error (SER) of - 6 diopter (D) to - 0.5 D were enrolled, and were randomized to LLRL group or control group. Children in the LLRL group underwent treatment twice daily, each lasting for 3 min, there was an interval of at least 4 h between treatments. Children in both groups were allowed to wear single-vision spectacles; no additional intervention was given to the control. The primary outcomes included change in cycloplegic SER and change in axial length (AL) during 6 months. RESULTS: The median 6-month changes in AL of the LLRL and control groups were - 0.06 mm (interquartile range, IQR - 0.15, 0) and 0.14 mm (IQR 0.07, 0.22), respectively. The difference between groups was significant (Z = 10.021, p < 0.001). The median 6-month changes in SER were 0.125 D (IQR 0, 0.375) and - 0.25 D (IQR - 0.5, 0) for the LLRL and control groups, respectively. The difference between groups was significant (Z = 8.827, p < 0.001). Compared with the control, the proportion of children with hyperopic shift in the LLRL group was higher (51.65% vs. 3.41%, p < 0.001), and the proportion of children with shortened AL in the LLRL group was higher (63.74% vs. 2.27%, p < 0.001). No adverse event was observed. CONCLUSION: 650 nm LLRL significantly slowed down the myopia progression in children aged 6-12 years, and there was no observable side effect in the short term.