Blue light exposure was found to increase the risk of age-related macular degeneration. Bright light does cause permanent retinal damage. If the light has the intensity of sunlight, short exposure times can cause damage. If the light is not quite so bright, chronic exposure over days to weeks can cause permanent damage. This is thought to be due to what is called photo-oxidative damage; the light reacts with the retina to produce molecules that are very reactive and cause damage to surrounding molecules. If light exposure is a risk factor for AMD, then it would be expected that people with lighter colored eyes, which let in more light, would have a higher risk.