A 12-month study found that daily low-level red light (LLRL) exposure produced good results in children with nonpathologic myopia, emmetropia, or low hyperopia treated at a single center, but the results may not be generalizable to a wider population.
Study Design
This was a randomized, single-masked clinical trial conducted at a single ophthalmology center in China to evaluate the safety and efficacy of daily treatment with 650-nm LLRL retinal irradiation in 336 children aged 6 to 12 years with spherical equivalent error (SER) of −6 D to +3 D. Children were randomized to either the treatment group, receiving LLRL via a head-worn device for 3 minutes twice daily (each session 4 or more hours apart), or to the control group with no intervention. In the device group, the children’s pupils were dilated using tropicamide eye drops, and the refractive error was measured with an autorefractor. Myopia, moderate myopia, and high myopia were defined as SER between −3 D and −0.5 D, SER between −6 D and −3 D, and−6 D or less, respectively, in any eye. Ocular biological parameters were measured using an optical biometer (Lenstar LS 900; HAAG-STREIT AG). Changes in cycloplegic SER and axial length (AL) were assessed at the 6- and 12-month follow-up visits.
Outcomes
At 12 months, statistically significant differences in both cycloplegic SER and AL were noted between the LLRL and control groups. Mean change in SER was +0.24 D in the LLRL group and −0.65 D in the control group, and mean change in AL was −0.11 mm and +0.26 mm, respectively, indicating less myopic progression and less ocular length elongation at 12 months in children receiving daily LLRL. Moreover, no retinal changes, particularly in choroidal thickness, were seen on masked fundus examination.
Limitations
One limitation of the study was that the head-worn device used and evaluated is patented by the eye center where the clinical trial was designed and performed. As such, the use of daily irradiation with such a device to prevent myopia progression cannot be generalized to other areas in China or the rest of the world.
Clinical Significance
These study results have limited clinical application, especially regarding the practical management of myopia progression and ocular elongation. The authors’ report of a single-site patented device warrants further investigation at independent sites to clarify and ensure long-term safety and efficacy in children with nonpathologic myopia, emmetropia, or low hyperopia.
Financial Disclosures: Dr. Jennifer Galvin discloses no financial relationships.