Light Therapy and Eye Safety PART II:
AMD - Age Related Blindness and Blue Light
Age-Related Macular Degeneration (AMD) is the leading cause of irreversible blindness in North America. Repeated exposure of the eye to high light intensities produces oxidative byproducts in the retina, which can lead to AMD. Some investigators link the development of AMD to the level of visible blue light exposure for twenty years or more before symptoms emerge. Evidence also indicates that increased daily exposure of young adults to blue visible light may advance AMD onset by 10 years. Refs.
Blue Light and the Retina
Photoreceptor cells and the nearby RPE (Retinal Pigment Epithelium) cells do not replicate after birth, and are continuously exposed to light energy and oxygen. Over a lifetime there is a build up of oxidative by-products within these cells. It is the absorption of blue light in particular that mainly causes the production of these indigestible oxidation by-products. The production and accumulation of oxidative waste products within these cells can lead to their malfunctioning and death. Refs 1, Refs 2, Refs 3.
It is the accumulation of oxidative byproducts in the retina that leads to AMD. In industrialized nations, AMD accounts for 50% of disease-related blindness. The proportion of people with AMD increases with age and most people who live over 90 years ultimately experience Age-related Macular Degeneration. Ref -See Science of AMD
For additional technical information on how visible light exposure contributes to age-related vision loss CLICK HERE
There is a growing understanding of the molecular pathways by which light-induced indigestible oxidative byproducts leads to AMD. We believe the connection between the cumulative insults to the retina from exposure to damaging levels of blue visible light and the development of AMD can now be established. Read more