$Refractive Correction$

Red Light Therapy (Myopia Progression Control)

1. What is red light therapy (myopia control)?

Repeated low-level red light therapy (RLRL) is a non-invasive treatment that suppresses myopia progression in children by irradiating the eye with low-intensity red visible light of specific wavelengths (mainly 650–670 nm). The standard protocol uses a dedicated handheld device, with sessions of 3 minutes twice daily, 5 days per week.

Positioning of RLRL therapy

RLRL therapy is a relatively new myopia progression control treatment for which evidence has rapidly accumulated since the 2020s. It is attracting attention as a “fourth option” after the three main conventional therapies (low-dose atropine eye drops, orthokeratology, and multifocal contact lenses), and most research has been conducted in East Asia, particularly in China.

Myopia is primarily caused by elongation of the axial length, with a 1 mm increase in axial length corresponding to approximately 3 diopters of myopia. Suppressing axial elongation is the most important goal of myopia management, and changes in axial length are the most important endpoint in evaluating the efficacy of RLRL therapy¹⁾.

Major complications associated with myopia include retinal detachment (30% increased risk per −1 D), myopic macular degeneration (58% increase), and open-angle glaucoma (20% increase)⁶⁾. RLRL therapy is positioned as a preventive intervention to reduce these long-term risks.

In Asian children, the prevalence of myopia is particularly high, and if left untreated and progresses to high myopia, the risk of serious complications such as retinal detachment and myopic macular degeneration increases significantly. The estimated risk increase per 1 D of myopia is 30% for retinal detachment, 58% for myopic macular degeneration, 20% for open-angle glaucoma, and 21% for posterior subcapsular cataract⁶⁾.

Since a 1 mm increase in axial length corresponds to approximately 3 D of myopia, suppressing axial elongation is the most important goal of myopia management. A meta-analysis by Haarman et al. (2020)⁷⁾ showed that the risk of complications increases exponentially with the severity of myopia, highlighting the importance of intervention at an early stage for improving long-term prognosis.

RLRL therapy, as one of the myopia progression control interventions alongside orthokeratology and low-dose atropine eye drops, has rapidly accumulated evidence since the 2020s. In Japan, it is being introduced as a self-funded treatment in some facilities. A systematic review by Yam et al. (2025) summarizes the evidence for multiple myopia progression control interventions, including RLRL therapy⁵⁾.

On the other hand, Bullimore et al. (2021) examined the risks and benefits of myopia management in general and pointed out that RLRL therapy carries a risk of retinal phototoxicity when irradiation parameters deviate⁶⁾. Proper device management and adherence to irradiation intensity and duration are prerequisites for safe use.

Q What is red light therapy?

RLRL therapy is a myopia progression suppression treatment that irradiates the eye with low-intensity (0.3–1 mW/cm²) red visible light in the 650–670 nm band for 3 minutes twice daily. It is thought to increase choroidal thickness and suppress axial elongation through photobiomodulation ³⁾. Currently, it is not approved in Japan and is provided as self-funded treatment under the management of a specialist.

2. Main Symptoms and Clinical Findings

Indicators of Treatment Efficacy

The efficacy of RLRL therapy is evaluated using the following objective indicators.

Axial length: Measured using an optical biometer. Changes are tracked before treatment and every 6 months.
Choroidal thickness: Measurement of subfoveal choroidal thickness (SFCT) using OCT. An increase in choroidal thickness is observed after RLRL irradiation. A 2-year follow-up study by Dong et al. (2023) confirmed an increase in choroidal thickness ²⁾.
Spherical equivalent refractive error: Objective assessment under cycloplegia.
Corrected visual acuity: Confirmation of stability of corrected visual acuity before and after treatment.

Safety Evaluation Precautions

RLRL therapy is considered to have few short-term adverse events due to its low intensity, but the following points should be regularly checked.

Risk of retinal toxicity: Excessive irradiation intensity, duration, or frequency may theoretically cause retinal damage ⁶⁾. Perform baseline OCT evaluation of retinal and choroidal layers before treatment and compare periodically.
Changes in visual acuity and color vision: Check for any decrease in visual acuity or color vision abnormalities during treatment.
Subjective symptoms: Pay attention to complaints such as glare, afterimages, or visual field abnormalities.

3. Causes and Risk Factors

Risk Factors for Myopia Progression

The following risk factors are involved in myopia progression, which is the target of RLRL therapy.

Early onset (especially between ages 6 and 12)
Both parents are myopic (especially if both are myopic)
Long near-work time (more than 3 hours per day)
Insufficient outdoor activity time (less than 1 hour per day)
Asian ethnicity (highest prevalence in East Asians)
Holden et al. (2016) predict that by 2050, about 50% of the world population will be myopic⁸⁾, increasing the social importance of early intervention.

4. Diagnosis and Examination Methods

Pre-treatment Evaluation

Before starting RLRL therapy, record baseline data and confirm indications through the following examinations.

Examination Item	Purpose	Main Points to Confirm
Cycloplegic refraction	Objective assessment of myopia degree	Spherical equivalent and astigmatism
Axial length measurement	Baseline setting and progression monitoring	Measured by optical biometry
Fundus examination	Pre-treatment retinal and choroidal status	Assessment of high myopia-related changes
OCT (macula and optic nerve)	Establishing baseline for retinal toxicity	Retinal and choroidal layer thickness
Slit-lamp examination	Exclusion of anterior segment diseases	Active inflammation and cataract

For cycloplegic examination, instillation of cycloplegic agents (e.g., Cyclogyl 1%) is essential in young children. Subjective refraction without cycloplegia may result in overestimation of myopic power.

Monitoring during treatment

The following schedule is recommended to confirm treatment efficacy and safety.

Timing	Content
1 month	Check compliance with eye drops, subjective symptoms, corrected visual acuity
Every 3–6 months	Axial length measurement, cycloplegic refraction, OCT (choroidal thickness, retinal evaluation)
Every year	Dilated fundus examination, OCT angiography (optional)

Q What tests are needed before treatment?

It is essential to record baseline values with cycloplegic refraction and optical biometry. Additionally, fundus examination and OCT should be performed to document the pre-treatment retinal and choroidal status, which will be used for safety monitoring during treatment. If high myopia is suspected, check for peripheral retinal degeneration or tears.

5. Standard treatment

The basic considerations for selecting patients eligible for RLRL therapy are as follows.

Recommended indications:

Ages 6 to 18 years (most studies target this age group)
Spherical equivalent myopia of −0.5 D or more with confirmed progression
Myopia confirmed by cycloplegic examination
Guardians are able to provide appropriate management

Situations requiring careful consideration:

Cases with a history or family history of retinal disease
Photosensitive disorders (e.g., xeroderma pigmentosum, cutaneous photosensitivity)
Use of photosensitizing medications

Situations where use should be avoided:

Active retinal disease (e.g., retinal degeneration, neovascularization)
Patients with a confirmed diagnosis of photosensitivity

Treatment Protocol

The standard treatment parameters adopted in major RCTs are shown below.

Parameter	Standard Value	Notes
Wavelength	650 nm (red visible light)	Some studies use 670 nm
Irradiance	0.3–1 mW/cm²	Incoherent light, non-laser
Exposure time	3 minutes/session	Twice daily (morning and evening)
Treatment frequency	5 days/week (school days only)	—
Treatment duration	12–24 months or more	Ongoing maintenance of effect required

The devices used are mainly Chinese-made dedicated handheld devices (e.g., Suneye) that have been used in research. They are designed for self-irradiation by patients at home, but initial setup and periodic checks are performed by a specialist.

Results of key RCTs

In a 1-year RCT by Jiang et al. (2022), the RLRL group showed significant suppression of axial elongation at 0.10 mm/year (control group 0.38 mm/year) ¹⁾. A 2-year follow-up by Dong et al. (2023) showed sustained suppression of axial elongation and confirmed an increase in choroidal thickness ²⁾.

In a multicenter RCT by Zeng et al. (2023), the 1-year spherical equivalent progression was −0.20 D in the treatment group (control group −0.71 D), suppressing myopia progression by approximately 72% ⁴⁾.

Comparison of RLRL therapy with other myopia progression suppression methods:

Intervention	Refractive suppression rate	Axial suppression rate	Key evidence
RLRL therapy	72% (Zeng 2023)	74% (Jiang 2022)	Multiple RCTs
Low-concentration atropine 0.05%	Up to 67%	—	LAMP study
Orthokeratology	—	43%	Si 2015 meta-analysis
MiSight (multifocal CL)	59%	52%	Chamberlain 2019
DIMS spectacles	55–59%	37–38%	Lam 2020 RCT

However, direct comparison requires caution due to differences in study design, target age, and treatment duration ⁵⁾. Low-concentration atropine eye drops (Rijusea® Mini 0.025%) are the only approved drug in Japan as of December 2024 ⁹⁾, and myopia management spectacle lenses (e.g., DIMS) ¹⁰⁾ are also recommended by the Japanese Myopia Society guidelines. RLRL therapy is being positioned as an option to combine with these approved interventions.

Compared with data from the 3-year RCT of MiSight (multifocal CL) ¹¹⁾, the 2-year RCT of DIMS spectacles ¹²⁾, meta-analysis of OK ¹³⁾, and the RCT of OK + atropine combination ¹⁴⁾, the short-term inhibition rate of RLRL therapy is favorable, but the major challenge is the lack of data beyond 5 years. The increasing trend of myopic maculopathy in Japanese individuals shown by the Hisayama Study ¹⁵⁾ further supports the medical importance of myopia management interventions including RLRL therapy.

Combination with Other Therapies

RLRL + low-concentration atropine: Since the mechanisms of action differ, additive or synergistic effects are expected, but verification in large-scale RCTs is ongoing ⁵⁾.
RLRL + orthokeratology: Reported as a combination selected for rapidly progressing cases.
When monotherapy is insufficient, consider combination with other myopia progression control therapies.

As of April 2026, RLRL therapy is not approved or covered by insurance in Japan and is provided as out-of-pocket treatment. It is necessary to fully explain the following to patients and guardians and obtain consent.

This treatment is not approved by the Japanese regulatory authorities.
Current evidence is mainly from 1-2 year observational studies, and long-term safety has not been established.
There is a theoretical risk of retinal toxicity if irradiation parameters are deviated ⁶⁾.
This is not a “treatment” for myopia but “progression control.”
Regular ophthalmological visits and safety monitoring are mandatory.

Q Can I receive red light therapy in Japan?

As of April 2026, RLRL therapy is not approved as a pharmaceutical or covered by insurance in Japan. It is offered as a self-funded treatment at some ophthalmology clinics. When visiting a clinic, it is important to thoroughly confirm with a specialist regarding indications, safety, and costs. Low-dose atropine eye drops (Rijusea® Mini 0.025%) were approved in December 2024 as the first domestic drug for myopia progression control and are an insured treatment option.

Position of RLRL in the mechanism of myopia progression control

While the main optical interventions for myopia progression control (orthokeratology, DIMS spectacles, multifocal CL) share the common mechanism of the “peripheral myopic defocus hypothesis,” RLRL therapy acts through a completely different pathway: photobiomodulation (PBM) → mitochondrial activation → improved choroidal blood flow → choroidal thickening → suppression of axial elongation. This different mechanism of action leads to expectations of synergistic effects when combined with other therapies ³⁾.

Additionally, a unique feature of RLRL therapy is the observation of an acute physiological response: choroidal thickness increases immediately after treatment ²⁾. This characteristic is not seen with other myopia progression control therapies, and measurement of choroidal thickness is considered useful as an immediate effect indicator of treatment.

6. Pathophysiology and detailed pathogenesis

OCT image of choroidal thickening in central serous chorioretinopathy (white arrows indicate thickened choroid)

Chhablani J, Barteselli G. Central serous chorioretinopathy with increased choroidal thickness. Wikimedia Commons. Figure 1. Source ID: commons:File:Central_serous_chorioretinopathy_with_increased_choroidal_thickness.png. License: CC BY-SA 3.0.

Optical coherence tomography (OCT) shows marked thickening of the subfoveal choroid, with a shallow serous detachment accompanied by subretinal fluid above the hyperreflective band indicated by white arrows. This corresponds to the relationship between increased choroidal thickness and suppression of axial elongation discussed in section “6. Pathophysiology and detailed pathogenesis.”

Photobiomodulation (PBM)

The main mechanism of RLRL therapy is proposed to be photobiomodulation (PBM) ³⁾. Red light in the 650–670 nm band is specifically absorbed by cytochrome c oxidase (Complex IV) in mitochondria, inducing the following biological responses.

Promotion of ATP production
Activation of cell signaling through moderate production of reactive oxygen species (ROS)
Vasodilation and increased blood flow via nitric oxide (NO) release
Improved choroidal circulation and thickening

Choroidal thickening and suppression of axial elongation

Consistent observations have shown that choroidal thickness increases after RLRL irradiation²⁾³⁾. This increase in choroidal thickness is thought to affect the rigidity of the eye wall and contribute to suppressing axial elongation. Increases in choroidal thickness have also been reported with orthokeratology and low-concentration atropine, drawing attention to the possibility that the choroid may be a common pathway for myopia progression control.

Basic mechanisms of myopia progression

Myopia progression is a biological process in which eye growth is regulated by signal transduction from the retina to the sclera, involving the following steps:

Peripheral hyperopic defocus serves as a driving signal for axial elongation
Dopamine-mediated growth-inhibitory signals brake axial elongation
Extracellular matrix remodeling of the sclera determines axial length
Choroidal thickening and thinning serve as biomarkers for axial length changes

RLRL therapy intervenes in these signaling pathways and brakes eye growth at the choroidal and scleral levels, but the full picture remains largely unclear³⁾. The quantitative risk of myopia complications shown in the meta-analysis by Haarman et al. (2020) is widely cited as the medical rationale for therapeutic intervention⁷⁾.

7. Latest research and future perspectives

Establishment of long-term efficacy and safety data

Current major RCTs have observation periods of 1–2 years, and long-term data over 5 years are scarce¹⁾²⁾. The persistence of effect after treatment discontinuation (carryover effect) is also not established, and studies tracking changes in myopia progression rate after treatment cessation are ongoing.

In the 2-year follow-up study by Dong et al. (2023), the RLRL treatment group showed sustained axial elongation suppression and choroidal thickening compared to the control group, and the effect was maintained with continuous use for 1 year²⁾. However, caution is needed in direct comparisons because study designs, irradiation parameters, and target ages differ between studies.

Quantification of retinal toxicity risk

Theoretically, excessive irradiation intensity, duration, or frequency could cause retinal damage. In the risk-benefit assessment of myopia management by Bullimore et al. (2021), the overall safety balance of optical and pharmacological interventions including RLRL therapy is discussed, emphasizing the importance of appropriate parameter management⁶⁾.

Studies aimed at setting safe irradiation limits and risk assessment are being conducted. In clinical practice, it is necessary to strictly adhere to irradiation intensity (0.3–1 mW/cm²), duration (3 minutes/session), and frequency (2 times/day, 5 days/week), and to perform regular calibration checks of the device.

From the perspective of phototoxicity, cumulative light exposure to photoreceptors and RPE is important, and caution is needed with irradiation exceeding recommended levels (especially high-intensity, prolonged off-label use). As indicated by the meta-analysis of myopia complications by Haarman et al. (2020)⁷⁾, it is important to individually assess the risk-benefit of RLRL therapy under the premise that appropriate myopia management can reduce the risk of serious complications.

Direct comparison with low-concentration atropine and orthokeratology

Direct comparison RCTs of RLRL therapy with orthokeratology and low-concentration atropine are being conducted. Establishment of personalized myopia management protocols considering the advantages and disadvantages of each therapy is expected⁵⁾.

Comparison of characteristics of the three major interventions (RLRL, OK, low-concentration atropine):

Intervention	Axial length suppression rate	Invasiveness	Convenience	Regulatory status in Japan
RLRL therapy	Approximately 60–72%	Non-invasive	Can be performed at home	Not approved (out-of-pocket)
Orthokeratology	30–50%	Contact lens wear	Overnight wear	Not approved (out-of-pocket)
Low-concentration atropine 0.025%	Approximately 62%	Eye drops	Instilled before bedtime	Approved

AI-Powered Prediction of Myopia Progression

Models that integrate axial length data, risk factors, and treatment response using AI to propose optimal treatment strategies for each patient are under development. They may also be applied to predict responders to RLRL therapy.

Trends Toward Domestic Approval

With accumulating evidence from China and Southeast Asia, dialogue with regulatory authorities in Japan may begin. The progress of domestic multicenter RCTs and regulatory approval is attracting attention. Against the backdrop of the global increase in myopia (Holden 2016: 4.9 billion by 2050⁸⁾), RLRL therapy is becoming established as one of the options for myopia management.

8. References

Jiang Y, Zhu Z, Tan X, et al. Effect of repeated low-level red-light therapy for myopia control in children: a multicenter randomized controlled trial. Ophthalmology. 2022;129:509-519.
Dong J, Zhu Z, Xu H, et al. Myopia control effect of repeated low-level red-light therapy in Chinese children: a randomized, double-blind, controlled clinical trial. Ophthalmology. 2023;130:198-204.
Wang W, Jiang Y, Zhu Z, et al. Chorioidal thickening as a potential therapeutic target in myopia management: a review of repeated low-level red light therapy. Surv Ophthalmol. 2023;68:1-12.
Zeng J, Liu Y, Wang Z, et al. Efficacy of repeated low-level red-light stimulation on slowing myopia progression and ocular growth in children with myopia: a randomized controlled trial. Transl Vis Sci Technol. 2023;12:22.
Yam JC, Zhang XJ, Zhang Y, et al. Interventions to reduce incidence and progression of myopia in children and adults. Prog Retin Eye Res. 2025.
Bullimore MA, Ritchey ER, Shah S, et al. The risks and benefits of myopia control. Ophthalmology. 2021;128:1561-1579.
Haarman AEG, Enthoven CA, Tideman JWL, et al. The complications of myopia: a review and meta-analysis. Invest Ophthalmol Vis Sci. 2020;61:49.
Holden BA, Fricke TR, Wilson DA, et al. Global prevalence of myopia and high myopia and temporal trends from 2000 through 2050. Ophthalmology. 2016;123:1036-1042.
低濃度アトロピン点眼液を用いた近視進行抑制治療の治療指針作成委員会. 低濃度アトロピン点眼液を用いた近視進行抑制治療の手引き. 日眼会誌. 2025;129(10):851-854.
近視管理用眼鏡ガイドライン作成委員会. 近視管理用眼鏡（多分割レンズ）ガイドライン（第1版）. 日眼会誌. 2025;129(10):855-860.
Chamberlain P, Peixoto-de-Matos SC, Logan NS, et al. A 3-year randomized clinical trial of MiSight lenses for myopia control. Optom Vis Sci. 2019;96:556-567.
Lam CSY, Tang WC, Tse DY, et al. Defocus incorporated multiple segments (DIMS) spectacle lenses slow myopia progression: a 2-year randomised clinical trial. Br J Ophthalmol. 2020;104:363-368.
Si JK, Tang K, Bi HS, et al. Orthokeratology for myopia control: a meta-analysis. Optom Vis Sci. 2015;92:252-257.
Kinoshita N, Konno Y, Hamada N, et al. Efficacy of combined orthokeratology and 0.01% atropine solution for slowing axial elongation in children with myopia: a 2-year randomized trial. Sci Rep. 2020;10:12750.
Ueda E, Yasuda M, Fujiwara K, et al. Trends in the prevalence of myopia and myopic maculopathy in a Japanese population: the Hisayama Study. Invest Ophthalmol Vis Sci. 2019;60:2781-2786.

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