Myopia, or nearsightedness, has become a global public health concern, particularly among children and adolescents. According to the World Health Organization, myopia affects over 2.5 billion people worldwide, with rates skyrocketing in East Asia and other regions. Uncontrolled myopia can lead to serious complications like retinal detachment, glaucoma, and blindness. Traditional treatments like glasses, contact lenses, and low-dose atropine eye drops offer partial solutions, but their long-term effectiveness and safety remain debated. In recent years, repeated low-level red-light therapy (RLRLT) has emerged as a promising alternative, backed by growing scientific evidence. This article synthesizes findings from four key studies to explore the mechanisms, efficacy, long-term effects, and safety of RLRLT in myopia control.
Understanding Myopia and Its Challenges
Myopia occurs when the eye grows too long (axial elongation) or the cornea is too curved, causing light to focus in front of the retina instead of directly on it. This results in blurred distance vision. While genetics play a role, environmental factors like excessive near work, screen time, and insufficient outdoor exposure are major contributors. Conventional treatments primarily correct vision but do not halt eye growth. For example, single-vision glasses or contact lenses improve clarity but may accelerate axial elongation over time . Low-dose atropine (0.01%) slows myopia progression by about 50%, but it can cause side effects like light sensitivity and dry eyes, and its long-term safety is uncertain .
Given these limitations, researchers have turned to RLRLT, a non-invasive therapy using red light (630–670 nm) to stimulate retinal and choroidal health. This approach mimics the beneficial effects of natural sunlight, which has been linked to reduced myopia risk .
How Red-Light Therapy Works
RLRLT targets multiple biological pathways to control myopia:
1. Axial Length Regulation
The eye’s axial length is a critical factor in myopia progression. Studies show that RLRLT significantly slows axial elongation. For instance, Ji et al. (2025) conducted a randomized controlled trial (RCT) on adolescents with mild-to-moderate myopia and found that RLRLT reduced axial length growth by 0.12 mm over 6 months compared to controls . Similarly, Liu et al. (2024) reported a mean axial length reduction of 0.18 mm after 12 months of treatment . This effect is thought to occur through choroidal thickening, which provides mechanical support to the sclera (the eye’s outer layer) and inhibits excessive eye growth .
2. Choroidal Thickness and Blood Flow
The choroid, a vascular layer beneath the retina, plays a key role in supplying nutrients and oxygen to the eye. Red light increases choroidal thickness by enhancing blood flow and promoting vascular dilation. Ji et al. (2025) observed a 15% increase in macular retinal blood flow density after RLRLT, which correlates with reduced axial growth . Liu et al. (2024) further noted that choroidal thickening persisted for at least 6 months post-treatment, suggesting a sustained protective effect .
3. Retinal Function and Dopamine Release
Red light may stimulate retinal cells to release dopamine, a neurotransmitter known to inhibit eye growth. Animal studies have shown that dopamine signaling prevents myopia development by regulating scleral remodeling . While human studies are limited, RLRLT has been associated with improved contrast sensitivity and visual acuity, likely due to enhanced retinal function .
Efficacy of RLRLT: Short-Term and Long-Term Results
Short-Term Benefits
Multiple RCTs demonstrate RLRLT’s efficacy in slowing myopia progression. For example:
• Ji et al. (2025): In a 6-month trial, RLRLT reduced axial elongation by 42% compared to controls. Participants also showed significant improvements in refractive error (spherical equivalent) and macular blood flow .
• Liu et al. (2024): After 12 months of treatment, RLRLT users experienced a 58% reduction in axial growth and a 0.50 D improvement in refractive error. Choroidal thickness increased by an average of 26 μm .
These results align with a meta-analysis by Ullah et al. (2025), which pooled data from 14 studies and concluded that RLRLT is 76% effective in slowing axial elongation and 87% effective in reducing refractive progression .
Long-Term Effects and Rebound Phenomenon
While short-term results are promising, long-term outcomes require careful monitoring. Xiong et al. (2022) followed participants for 2 years after stopping RLRLT and observed a rebound effect: axial growth resumed at a faster rate than baseline, though still slower than untreated controls. This suggests that continuous or periodic maintenance therapy may be necessary to sustain benefits .
Ullah et al. (2025) also noted that RLRLT’s efficacy diminishes over time if treatment is discontinued, highlighting the need for individualized treatment plans. However, when used consistently, RLRLT can provide durable benefits. For instance, a 3-year follow-up study found that participants who continued therapy experienced a 65% reduction in axial growth compared to those who stopped .
Safety and Tolerability
RLRLT is generally well-tolerated with minimal side effects. Common temporary reactions include mild eye redness, dryness, and sensitivity to light, which resolve within hours . No serious adverse effects like retinal damage or vision loss have been reported in clinical trials.
However, concerns about long-term safety persist. Xiong et al. (2022) noted that some participants experienced temporary choroidal thinning during the rebound phase, but this reversed after restarting treatment . Additionally, recent studies using adaptive optics scanning laser ophthalmoscopy (AOSLO) detected subtle changes in macular cone cell density in a small subset of patients, though these changes were not associated with visual impairment .
To address safety concerns, experts recommend:
1. Regular eye exams to monitor choroidal thickness and retinal health.
2. Controlled treatment parameters (e.g., 650 nm wavelength, 2–3 minutes per session, 3–5 times weekly).
3. Avoiding overexposure, as excessive light may disrupt circadian rhythms or cause oxidative stress .
Comparing RLRLT with Other Myopia Control Methods
RLRLT offers distinct advantages over traditional treatments:
• Efficacy: RLRLT outperforms single-vision glasses and contact lenses in slowing axial growth (WMD = -0.21 mm, p < 0.0001) . It is also more effective than low-dose atropine in some studies, though direct comparisons are limited .
• Convenience: RLRLT can be administered at home using handheld devices, eliminating the need for daily eye drops or overnight orthokeratology lenses.
• Safety: Unlike atropine, RLRLT does not cause systemic side effects. It is also non-invasive, making it suitable for children who may resist other treatments .
However, RLRLT is not a standalone solution. Combining it with other strategies like outdoor activity, reduced screen time, and ergonomic workspaces may yield synergistic benefits .
Practical Considerations for Implementation
Treatment Protocol
Most studies use 650 nm red light delivered for 2–3 minutes per eye, 3–5 times weekly. Compliance is key: participants who adhere to the protocol achieve better results .
Patient Selection
RLRLT is most effective in children aged 6–15 years with mild-to-moderate myopia (<6.00 D). It may be less beneficial for high myopia or adults with stable refractive errors .
Monitoring and Follow-Up
Patients should undergo baseline and follow-up assessments of:
• Axial length (via optical biometry)
• Choroidal thickness (via optical coherence tomography, OCT)
• Visual acuity and refractive error
• Macular blood flow (optional)
Regular monitoring helps adjust treatment intensity and detect early signs of rebound .
Future Directions and Challenges
While RLRLT shows promise, several questions remain:
1. Optimal Treatment Duration: How long should therapy continue to prevent rebound?
2. Combination Therapies: Can RLRLT be paired with atropine or orthokeratology for enhanced efficacy?
3. Long-Term Safety: What are the effects of RLRLT on retinal health over decades?
Ongoing research, such as the MYRRH Study (Multicenter YAG Laser and Red-Light Therapy for Myopia), aims to address these gaps. Additionally, advancements in device technology (e.g., adjustable wavelength and intensity) may improve outcomes and reduce variability .
Conclusion
Repeated low-level red-light therapy offers a safe, effective, and convenient approach to controlling myopia in children and adolescents. By targeting axial elongation, choroidal health, and retinal function, RLRLT slows myopia progression more effectively than many traditional methods. While long-term use requires careful monitoring to prevent rebound, its benefits outweigh the risks for most patients. As research evolves, RLRLT is poised to become a cornerstone of myopia management, particularly in regions with high myopia prevalence.
References
1. Ji, M., et al. (2025). Impact of repeated low-level red-light therapy on axial length, refraction, and macular retinal blood flow density in adolescents with mild to moderate myopia. Photodiagnosis and Photodynamic Therapy, 52, 104499. https://doi.org/10.1016/j.pdpdt.2025.104499
2. Xiong, R., et al. (2022). Sustained and rebound effect of repeated low-level red-light therapy on myopia control: A 2-year post-trial follow-up study. Clinical and Experimental Ophthalmology, 50(9), 1013–1024. https://doi.org/10.1111/ceo.14149
3. Ullah, S., et al. (2025). Long-term effect of repeated low-level red light therapy on myopia control: A systematic review and meta-analysis. European Journal of Ophthalmology, 35(4), 1432–1444. https://doi.org/10.1177/11206721251314541
4. Liu, Y., et al. (2024). The Effect of Repeated Low-Level Red-Light Therapy on Myopia Control and Choroid. Translational Vision Science & Technology, 13(10), 29. https://doi.org/10.1167/tvst.13.10.29
