"Light Therapy and Retinal damage "

Ocular Experts Caution Against the Use of Bright Light and Blue Light Therapy Lamps

Many experts link the development of Age-related Macular Degeneration (AMD) to the cumulative lifetime exposure to blue light wavelengths. Dr. S. Beatty, director of the Macular Pigment Pigment Research Group (MPRG) stated "It is photo-oxidative stress, or the cumulative exposure to free radicals from blue light over a lifetime that causes AMD". The European Eye (EUREYE) Study "found that the combination of blue light exposure and low plasma concentrations of antioxidants was also associated with the early stages of AMD, which are common in the population, and that blue light exposure in middle age might be more damaging than at younger ages." Studies have indicated that a moderate increase in lifetime exposure to blue light can advance the onset of this blinding disease by several years.

This has led a number of experts to caution against the use of bright and blue light therapy lamps. As Dr.s L. Lack and H.Wright stated, "It should be noted that broad-spectrum white light, traditionally used for bright light therapy, also contains blue light of potential concern particularly for very high intensity, long- duration exposure. Clearly, the safety of bright light therapy for people needs investigating. In the meantime it would be suggested that light in the 500 to 530 nm wavelength range (blue-green) should still be effective while avoiding the putative blue hazard." in Clinical Management of Delayed Sleep Phase Disorder. Behavioral Sleep Medicine 2007, 5(1):57-76
Sunnex Biotechnologies patented GreenLIGHT technology screens out hazardous blue light wavelengths and eliminates the risk of eye damage inherent in the use of bright light lamps and light therapy lamps that primarily emit blue light.

The consequences of AMD for people who use light therapy can be severe. As reported in the journal Science on the 25th anniversary of the development of light therapy, the first person to use bright light therapy explained how light therapy became less and less effective for him over the years as his eyesight faded, and concluded "Now I can hardly see, and all hell has broken loose... I have had periods of depression lasting over a year".

It is now possible to demonstrate that cumulative blue light exposure is a stongly contributing factor in the development of AMD. In the link below we have included a brief discussion on the basis for this. As the most recent studies appear to confirm that blue light wavelengths shorter than 480 nm provides no advantage over the use of much less hazardous longer wavelengths in light therapy (click here), the risk of causing severe impairment to vision from the use of light therapy lamps that emit short wavelength blue light appears to be unwarranted.
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