Eye Safety - Red Light & Infrared Saunas

Combined red light and near-infrared (NIR) saunas emit wavelengths in the 600–700 nm (red) and 700–1400 nm (NIR) ranges, commonly around 630–660 nm and 800–850 nm.[1][2] These wavelengths fall directly within the documented hazard zones for both retinal thermal injury and lens damage. Research shows that the 380–1400 nm spectrum—including all red and NIR sauna wavelengths—can cause thermal injury to the retina.[3] NIR radiation (IR-A, 700–1400 nm) also penetrates the eye and is associated with molecular changes and cataract formation.[4]

Thermal injury to the cornea and lens can occur in the 780–3000 nm range, and international safety guidelines (ICNIRP) have established exposure limits to prevent cataractogenesis.[5] Because red/NIR sauna wavelengths (600–850 nm) lie squarely inside these hazardous ranges, appropriate eye protection is advised.

What Type of Eye Protection Works?

Near-infrared-blocking spectacle lenses (NIBSL)—especially those with specialized NIR-blocking coatings—are currently considered the most effective protective eyewear for red/NIR sauna exposure.[6] These lenses:

• Provide superior attenuation of 780–1400 nm NIR radiation

• Maintain normal vision, color perception, and clarity

• Reduce thermal transfer to ocular tissues

Coated NIBSL lenses outperform standard polymer lenses, and laboratory models show they reduce heat buildup in the eye—an important consideration, because NIR wavelengths commonly used in saunas (e.g., 808 nm) have been shown to cause acute lens opacification and cataract formation at relatively low power and short exposure times.[7][8]

Occupational and animal studies further confirm that infrared exposure can lead to acute and chronic ocular damage, including cataracts and corneal/lens molecular changes.[8][9][10]

Important: Standard UV-blocking eyewear does not protect against NIR radiation.

What Wavelengths Are Used in Red Light Therapy?

Red light therapy, formally known as photobiomodulation (PBM), uses:

• Red light: 620–700 nm

• Near-infrared (NIR): 700–1440 nm[11]

These wavelengths directly overlap with those emitted by combined red/NIR saunas (typically 630–660 nm and 800–850 nm).[11][12] Sauna wavelengths are essentially identical to those used in clinical PBM devices.

The therapeutic PBM range (600–1100 nm) fits entirely within the same retinal and lens hazard zones (380–1400 nm and 700–1400 nm) described earlier.[12]

Thus, both red light therapy and red/NIR saunas use wavelengths associated with documented ocular risk—making protective eyewear equally important in both settings.

In Summary

• Combined red/NIR saunas use wavelengths (600–850 nm) that fall within established hazard zones for retinal thermal injury and cataract formation.

• NIR-blocking spectacle lenses (NIBSL) offer the most effective protection and outperform standard clear, tinted, or UV-blocking eyewear.

• Red light therapy uses the same wavelength ranges, meaning the same eye-safety considerations apply.

Disclaimer:

This content is for informational purposes only. It is not intended to replace professional medical or mental health advice, diagnosis, or treatment from your healthcare provider. Always consult your physician or qualified health provider with any questions you may have regarding a medical or mental health condition. Use of this content does not establish a patient-provider relationship.

References:

1. Tsai, S. R., & Hamblin, M. R. (2017). Biological effects and medical applications of infrared radiation. Journal of Photochemistry and Photobiology B: Biology, 170, 197–207. https://doi.org/10.1016/j.jphotobiol.2017.04.014

2. Xue, F., & Zhou, Y. (2025). Illuminating eye care: The promise and future of red light therapy in ophthalmology. Graefe’s Archive for Clinical and Experimental Ophthalmology, 263(6), 1515–1522. https://doi.org/10.1007/s00417-025-06800-1

3. Madjidi, F., & Behroozy, A. (2014). Replacing effective spectral radiance by temperature in occupational exposure limits to protect against retinal thermal injury from light and near IR radiation. Journal of Occupational and Environmental Hygiene, 11(10), 688–694. https://doi.org/10.1080/15459624.2014.904516

4. Dadoukis, P., Klagas, I., Komnenou, A., et al. (2013). Infrared irradiation alters the expression of matrix metalloproteinases and glycosaminoglycans in the cornea and crystalline lens. Graefe’s Archive for Clinical and Experimental Ophthalmology, 251(8), 1929–1936. https://doi.org/10.1007/s00417-013-2349-9

5. Madjidi, F., & Mohammadi, J. (2015). A new method to calculate the threshold temperature of a perfect blackbody to protect cornea and lens in the range of 780–3,000 nm. Health Physics, 108(1), 8–14. https://doi.org/10.1097/HP.0000000000000173

6. Pyo, J. Y., Kim, M. C., Oh, S. J., Mah, K. C., & Jang, J. Y. (2025). Evaluation of optical and thermal properties of NIR-blocking ophthalmic lenses under controlled conditions. Sensors, 25(11), 3556. https://doi.org/10.3390/s25113556

7. Okuno, T., Kojima, M., Hasanova, N., Ishiba, Y., & Sliney, D. H. (2022). Threshold ocular exposure to near-infrared radiation for causing acute opacification in the rabbit lens. Photochemistry and Photobiology, 98(4), 945–948. https://doi.org/10.1111/php.13555

8. Okuno, T., Kojima, M., Yamaguchi-Sekino, S., et al. (2021). Cataract formation by near-infrared radiation in rabbits. Photochemistry and Photobiology, 97(2), 372–376. https://doi.org/10.1111/php.13342

9. Dadoukis, P., Klagas, I., Komnenou, A., et al. (2013). Infrared irradiation alters expression of matrix metalloproteinases and glycosaminoglycans in the cornea and lens. Graefe’s Archive for Clinical and Experimental Ophthalmology, 251(8), 1929–1936. https://doi.org/10.1007/s00417-013-2349-9

10. Söderberg, P. G., Talebizadeh, N., Yu, Z., & Galichanin, K. (2016). Does infrared or ultraviolet light damage the lens? Eye, 30(2), 241–246. https://doi.org/10.1038/eye.2015.266

11. Maghfour, J., Ozog, D. M., Mineroff, J., et al. (2024). Photobiomodulation CME Part I: Overview and mechanism of action. Journal of the American Academy of Dermatology, 91(5), 793–802. https://doi.org/10.1016/j.jaad.2023.10.073

12. Zhang, F., Li, Q., Qin, W., et al. (2024). A study of the biological effects of low-level light. Lasers in Medical Science, 39(1), 74. https://doi.org/10.1007/s10103-024-04018-x