Uncontrolled, frequent or long-term exposure to Near Infrared can cause thermal burns and ageing effects such as “Bakers Arms” or “Glassblowers Face” (Cho & others, 2009). Eye damage can also occur because Near Infrared transmits as far as the cornea – implying time limits or goggles should be employed when eye contact is likely (Voke 1999). The colour of the Near IR light itself is not relevant to its effects (ICNIRP 2006) as we have also heard statements like “it doesn’t affect horses, because they can’t see red”.
Reducing the wattage; reducing the voltage into the bulb or just moving the lamp further away does does not make Near IR “safer” per se, it just reduces the peak intensity of the lamp to a point where the wavelengths will be in the Medium to Far Infrared bands and the physical properties claimed as being “Near IR” no longer relevant anyway. We have seen a number of Near Infrared heater dealerships selling their lamps with dimmer switches and still claiming the “medical” benefits of Near Infrared.