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Potential Inhibitory Effect of LED-Sourced Red Light Therapy on Ocular Growth in Normal and Myopic Chicks
Fengjuan Yu1,2, Kit-Ying Choy1,3, Jingfang Bian1,2
1Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Kowloon, Hong Kong.
International Journal of Molecular Sciences
|June 26, 2026
Summary
Light-emitting diode (LED)-sourced red light (RL) shows promise for controlling myopia progression. Moderate to high intensities of 664 nm LED RL effectively slowed eye growth in myopic chicks, with high intensity also protecting fellow eyes.
Area of Science:
- Ophthalmology
- Cell Biology
- Biophotonics
Background:
- Repeated low-level red light (RLRL) is clinically used to manage myopia progression.
- Concerns regarding laser safety promote the investigation of light-emitting diode (LED)-sourced red light (RL) as an alternative.
- Understanding the cellular and ocular effects of LED RL is crucial for myopia control strategies.
Purpose of the Study:
- To evaluate the in vitro cellular effects of LED-sourced RL on photoreceptor cells.
- To investigate the in vivo effects of varying intensities of LED-sourced RL on ocular growth in normal and myopic chick models.
- To determine the efficacy of LED RL in preventing or attenuating myopia progression.
Main Methods:
- Mouse photoreceptor 661W cells were exposed to 625 nm and 664 nm LED RL, assessing cytochrome c oxidase (CCO) activity and cell viability.
- Chicks with normal visual conditions or monocular -5D lens-induced myopia (LIM) were treated with 664 nm LED RL at low, moderate, or high intensities for 10 days.
- Ocular growth parameters, including vitreous chamber depth (VCD) and axial length (AL), were measured.
Main Results:
- 664 nm LED RL demonstrated superior activation of CCO and enhanced cell viability in 661W cells compared to 625 nm RL and white light.
- Low-intensity 664 nm LED RL inhibited ocular elongation in normally growing chicks but had no significant effect in LIM eyes.
- Moderate and high intensities of 664 nm LED RL significantly attenuated myopia progression in LIM eyes, reducing VCD and AL elongation.
- High-intensity RL also protected the fellow eyes of LIM chicks from myopic shift and excessive elongation.
Conclusions:
- LED-sourced 664 nm RL effectively activates CCO, reduces apoptosis, and promotes cell viability in vitro.
- LED RL can inhibit ocular growth in both normal and lens-induced myopic chicks.
- Intensity-dependent effects of LED RL suggest potential for therapeutic applications in myopia management.
