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.