Risks of red light therapy: eyes, burns, drugs, overdosing

Red light therapy is generally safe at the doses used in trials, where side effects were mostly mild redness. The main risks of red light therapy are eye damage from staring into bright LEDs or lasers, burns from hot devices, reactions with light-sensitizing drugs, and overdosing. Red laser treatment for myopia in children carries the clearest documented harm.

The research on benefits is in does red light therapy work. This page covers what can go wrong and how to avoid it.

The risks of red light therapy at a glance

Risk	Who is most exposed	How strong is the evidence	What to do
Retinal damage	Children on red laser myopia therapy; anyone staring into a device	Case reports plus lab measurements of devices	Never look into the light. Use goggles or close your eyes
Thermal skin injury	Users of handheld or contact devices, long sessions	Lab heating data; serious burns rarely reported	Keep the stated distance, stop if skin feels hot
Drug reactions	People on photosensitizers or after photodynamic therapy	Drug labels and a review of laser cases	Ask a doctor or pharmacist before starting
Pigment changes	People with melasma or darker skin	Small clinical studies of visible light	Avoid devices with blue LEDs on the face
Overdosing	Daily long sessions “to speed things up”	Lab and animal studies	Follow trial-based session times
Bad dosing from cheap devices	Buyers of unverified gadgets	A 5-device lab study	Buy devices with measured output and clear specs

Is red light therapy safe for your eyes?

For a healthy adult using an LED panel with eyes closed or covered, the risk looks low. The problem is light that goes straight into an open eye, which is exactly what red laser myopia devices do.

Your eye protects itself from bright visible light by squinting, looking away and shrinking the pupil. International exposure guidelines set a separate retinal limit for infrared sources “without a strong visual stimulus” and assume the pupil stays fully open at 7 mm, because that protection does not kick in.¹ A near-infrared-only mode on a panel falls into this category.

Red light therapy for myopia: the retinal damage cases

Repeated low-level red light (RLRL) therapy shines a red laser into a child’s eyes. In a 264-child trial using 650 nm light for 3 minutes twice a day, it cut eye growth to 0.13 mm a year against 0.38 mm with glasses alone, and OCT scans found no structural damage.² A 2026 meta-analysis of 28 trials (3,573 children) also found side effects mostly mild and temporary, but called for longer trials with proper retinal safety checks.³

Rare harm still slips past trials of that size:

• A 12-year-old girl used an RLRL device for about 5 months. She reported unusual light sensitivity and long afterimages, then blurred vision in both eyes. Her best-corrected vision fell from 20/20 to 20/30, and scans showed damage to the light-sensing layer of the fovea. Three months after stopping, it had partly recovered, to 20/25.⁴
• A 2024 lab study found that 3 minutes of continuous viewing approached or exceeded the maximum permissible exposure for both devices tested.⁵
• A 2026 follow-up tested four devices. Two laser units reached safety limits in 2.8 and 1.4 seconds with a 7 mm pupil, far short of the 180-second treatment. A diffuse LED device took 22,761 seconds. The authors noted that China has reclassified red laser devices into its highest-risk class, Class III.⁶

One case report cannot prove the device caused the damage. Still, if your child is offered RLRL, ask the eye doctor how they will monitor the retina.

Red light therapy for eyes: the prescription exception

Light aimed at the eye is not always harmful. The FDA has authorized the Valeda Light Delivery System, a prescription device using 590, 660 and 850 nm LEDs, for some people with dry age-related macular degeneration. After about two years, treated eyes read about one more line on the eye chart than untreated eyes.⁷

Its label excludes people with known sensitivity to these wavelengths, people with light-triggered conditions such as epilepsy or migraine, and anyone who used a photosensitizing drug affected by those wavelengths in the previous 30 days without checking with a doctor.⁷ This was a prescription device with set doses. It is not evidence that looking into a home panel is good for your eyes.

Can red light therapy burn your skin?

Published reports of serious burns from home red light devices are hard to find. The risk is mostly heat, not the light itself.

A 2025 lab study of five handheld home LED devices found one that raised the surface of pig skin by 5.7 to 7.8 °C over 3 minutes at 106 mW/cm², and 4.1 to 6.2 °C at 5 mm deep. Another device’s metal casing reached 32 to 44 °C after 5 minutes.⁸ Normally, heat on the skin and cornea makes you pull away within seconds.¹ That reflex does not help if you fall asleep under a panel, strap a device on, or have reduced feeling in the area.

To lower the risk:

• Keep the distance the manufacturer specifies, and do not press a warm device against skin.
• Do not use a panel in bed if you might fall asleep.
• Skip areas with numbness, fresh scars or broken skin unless a clinician has said otherwise.
• Stop if the skin turns hot, painful or blistered.

Which medications make red light therapy risky?

The FDA describes drug-related sun sensitivity as a reaction to ultraviolet light, not red. It lists antibiotics, antifungals, antihistamines, cholesterol drugs, diuretics, NSAIDs, oral contraceptives, phenothiazines, psoralens, retinoids, sulfonamides and sulfonylureas as medicines that can cause sun sensitivity.⁹ A review of lasers and photosensitizing drugs found no published reports of complications, and recommended a database matching each drug to the wavelengths that activate it.¹⁰

A few drugs are activated by red light directly, and these are the ones that matter most:

Drug	Activating light	Label warning
Aminolevulinic acid gel (Ameluz), used for photodynamic therapy	Red lamp around 635 nm	Protect treated skin from sunlight and intense light for 48 hours11
Verteporfin (Visudyne), used for eye disease	Laser at 689 nm	Avoid direct sunlight and bright indoor light for 5 days12

If you have had photodynamic therapy, wait for your doctor’s all-clear before using a home panel. If you take any long-term medication, ask a pharmacist whether it reacts to visible or near-infrared light.

Does red light therapy make melasma worse?

Red light on its own does not seem to darken skin. In one study, 415 nm blue-violet light caused dose-dependent darkening lasting up to 3 months, while 630 nm red light caused none.¹³ A second study (25 volunteers) found blue light accounted for 71% of visible-light pigmentation and red light had no significant effect.¹⁴

The catch is mixed devices. In one study of 20 volunteers with skin types IV to VI, visible light from 400 to 700 nm caused darker, longer-lasting pigmentation than UVA1, while lighter type II skin did not darken.¹⁵ Three of the five home devices in the lab study above included 460 nm blue LEDs.⁸ Dermatologists also advise extra care with skin of color because these wavelengths can act differently in different skin types.¹⁶

If you have melasma, choose red-only or red plus near-infrared, avoid blue modes on the face, and keep wearing sun protection.

Can you overdo red light therapy?

Yes. Light therapy follows a biphasic dose curve: small doses stimulate tissue, and big doses lose the effect or start to inhibit it. In a mouse wound study, 2 J/cm² healed fastest, while 50 J/cm² made wounds expand more than in untreated mice.¹⁷ Human data on overdosing are thin, and there is no evidence that sessions longer or more frequent than those used in trials work better.

For panels used to wind down at night, dose matters less than timing and brightness. See red light therapy for sleep and the best light color for sleep.

Are cheap red light devices more dangerous?

Not necessarily more dangerous, but often impossible to dose correctly. A 2025 lab study of five randomly chosen home LED devices found wide variation in wavelength, power and irradiance, unstable output, and a 74° beam spread that the makers’ dosing instructions ignored.⁸ If you do not know the real irradiance at your distance, you cannot tell if you are underdosing or overdosing.

Look for devices that publish measured irradiance at stated distances, list exact wavelengths, and include eye protection. Our red light therapy device listings show these specs where they are published.

Is red light therapy FDA approved?

No home device is “FDA approved” for red light therapy. Devices that carry FDA clearance went through a 510(k), meaning the FDA found them substantially equivalent to a device already sold legally. Approval is a separate, stricter process called premarket approval.¹⁸ Over-the-counter wrinkle devices, for example, are Class II and need a 510(k).¹⁹

Clearance applies to one use, such as wrinkles or hair loss, not to every claim on the box. You can look up a device’s 510(k) number in the FDA database. Our guide to FDA-cleared red light therapy devices explains how.

Who should not use red light therapy without medical advice

• People taking photosensitizing drugs, or who had photodynamic therapy in the past month.
• Anyone with a retinal disease or another serious eye condition.
• People with epilepsy or light-triggered migraine, which the FDA-authorized eye device lists as an exclusion.⁷
• People with melasma, especially with devices that include blue LEDs.
• Children, for any eye-directed treatment, unless an eye doctor is monitoring them.

This page is general information, not medical advice.

Footnotes

1. International Commission on Non-Ionizing Radiation Protection. ICNIRP guidelines on limits of exposure to incoherent visible and infrared radiation. Health Phys. 2013;105(1):74-96. doi:10.1097/HP.0b013e318289a611 ↩ ↩²

2. 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(5):509-519. doi:10.1016/j.ophtha.2021.11.023 ↩

3. Lin LY, Hsu CH, Su H, et al. Duration-dependent efficacy and clinical safety of repeated low-level red-light therapy for paediatric myopia: a systematic review and meta-analysis. Clin Exp Ophthalmol. 2026;54(5):630-652. doi:10.1111/ceo.70105 ↩

4. Liu H, Yang Y, Guo J, Peng J, Zhao P. Retinal damage after repeated low-level red-light laser exposure. JAMA Ophthalmol. 2023;141(7):693-695. doi:10.1001/jamaophthalmol.2023.1548 ↩

5. Ostrin LA, Schill AW. Red light instruments for myopia exceed safety limits. Ophthalmic Physiol Opt. 2024;44(2):241-248. doi:10.1111/opo.13272 ↩

6. Ostrin LA, Schill AW. Safety evaluation of 4 red light therapy devices for myopia. JAMA Ophthalmol. 2026;144(3):255-258. doi:10.1001/jamaophthalmol.2025.5660 ↩

7. US Food and Drug Administration. De Novo classification request for Valeda Light Delivery System (DEN230083). accessdata.fda.gov ↩ ↩² ↩³

8. Cronshaw M, Parker S, Hamadah O, Arnabat-Dominguez J, Grootveld M. Photobiomodulation LED devices for home use: design, function and potential: a pilot study. Dent J (Basel). 2025;13(2):76. doi:10.3390/dj13020076 ↩ ↩² ↩³

9. US Food and Drug Administration. The sun and your medicine. fda.gov ↩

10. Kerstein RL, Lister T, Cole R. Laser therapy and photosensitive medication: a review of the evidence. Lasers Med Sci. 2014;29(4):1449-1452. doi:10.1007/s10103-014-1553-0 ↩

11. Biofrontera. AMELUZ (aminolevulinic acid hydrochloride) topical gel, prescribing information. 2026. accessdata.fda.gov ↩

12. VISUDYNE (verteporfin for injection), prescribing information. 2023. accessdata.fda.gov ↩

13. Duteil L, Cardot-Leccia N, Queille-Roussel C, et al. Differences in visible light-induced pigmentation according to wavelengths: a clinical and histological study in comparison with UVB exposure. Pigment Cell Melanoma Res. 2014;27(5):822-826. doi:10.1111/pcmr.12273 ↩

14. Marionnet C, Piffaut V, Sasai J, et al. A precise analysis of the relative contribution of UVA1 and visible light colour domains in solar light-induced skin pigmentation. J Eur Acad Dermatol Venereol. 2023;37(Suppl 4):3-11. doi:10.1111/jdv.18948 ↩

15. Mahmoud BH, Ruvolo E, Hexsel CL, et al. Impact of long-wavelength UVA and visible light on melanocompetent skin. J Invest Dermatol. 2010;130(8):2092-2097. doi:10.1038/jid.2010.95 ↩

16. Mineroff J, Maghfour J, Ozog DM, et al. Photobiomodulation CME part II: clinical applications in dermatology. J Am Acad Dermatol. 2024;91(5):805-815. doi:10.1016/j.jaad.2023.10.074 ↩

17. Huang YY, Chen AC, Carroll JD, Hamblin MR. Biphasic dose response in low level light therapy. Dose Response. 2009;7(4):358-383. doi:10.2203/dose-response.09-027.Hamblin ↩

18. US Food and Drug Administration. Premarket notification 510(k). fda.gov ↩

19. US Food and Drug Administration. Product classification: light based over the counter wrinkle reduction (product code OHS, 21 CFR 878.4810). accessdata.fda.gov ↩