Transient ocular effects of red light exposure in young adults

Red laser therapy has recently gained attention as a potential myopia treatment in children. However, concerns regarding the safety of directing red laser at the fovea have raised caution. As a result, there is growing interest in identifying alternative, safer methods of red light administration for myopia control. This study investigated whether short-term exposure to red LED light induces ocular vascular changes similar to those previously reported with red laser exposure.

Twenty healthy adults (28 ± 5 years) participated in four experimental sessions each: (1) morning red LED exposure, (2) evening red LED exposure (both 5 minutes), (3) morning control, and (4) evening control. Red light (λ = 626 nm, irradiance = 0.11 mW/cm²) was delivered to the right eye using a Ganzfeld dome. Biometry, optical coherence tomography (OCT), and OCT angiography (OCTA) were performed at baseline and at 5, 30, and 60 minutes post-exposure. Changes were analyzed using two-way repeated measures ANOVAs.

There were no significant differences in axial length, choroidal thickness, or perfusion density of the superficial or deep vascular complexes between red light exposure and control conditions at 5, 30, or 60 minutes in the morning or evening (P > 0.05 for all).

Findings show that short-term exposure to red LED light does not induce significant transient changes in ocular vascular structures. While some studies have related short term choroidal thickening or increased blood flow to longer term myopia control efficacy, it cannot be concluded from the current study whether red LEDs would be effective.