When picking out a pair of sunglasses this summer, it's best to avoid blue-tinted lenses and instead to choose yellow- or amber-tinted lenses, advises an eye researcher in New York.
"Yellow- and amber-tinted sunglasses filter out blue light, reducing the amount of blue light getting to your eye," Dr Janet Sparrow, professor of ophthalmic science at Columbia University Medical Center in New York explained in an interview with Reuters Health.
Sparrow is researching blue light exposure from sunlight as one of the causes of age-related macular degeneration, a degenerative eye disorder that is the leading cause of blindness in the elderly.
"There are compounds that accumulate in some retinal cells with age and these compounds are light-sensitive," Sparrow said. Blue light excites these retinal cell compounds, fuelling the release of harmful free radicals.
"We see light as white, but contained in that white light are actually different colours of light, like the colours of the rainbow and the wavelengths in the blue portion of the spectrum are able to maximally excite these compounds and imitate oxidative processes that can damage retinal cells," Sparrow further explained.
Therefore, most people, Sparrow said, regardless of age, should avoid blue-tinted sunglasses. "A blue lens actually selects out blue light, which is not good - you want to diminish the blue light. A yellow lens filters blue light, so a yellow lens would reduce blue and that's what you want."
Dark-tinted lenses are also a good choice in sunglasses, Sparrow said, because they decrease exposure to all colors of light.
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