Infrared LEDs are often used in treatment plans for sports injuries and burns, as their light is able to pass through up to an inch of tissue. The infrared rays can benefit cells by promoting an increase in DNA and RNA activity. Light with wavelengths between 600 and 900 nanometers passes through the blood and water in tissue more efficiently than light at any other wavelength.
There are several concerns regarding human exposure to the infrared light given off by specially designed infrared LEDs. The human eye does not properly register infrared light. The pupil should normally close to protect the retina in the presence of bright light. When exposed to bright LED infrared light, the eye will not react and the resulting overexposure can cause permanent damage.
There are several measures one can take to prevent eye damage when working with infrared LEDs. While the risk of eye damage from working with a small amount of infrared LEDs is very low, people who work with around a lot of infrared LEDs should be fitted with protective goggles as a precautionary measure.