HOUSTON, June 16 (UPI) — A U.S. professor of optometry suggests gray lenses for sunglasses allow for more natural color vision and reduce light intensity.
However, Dr. Jan Bergmanson of the University of Houston, who is also founding director of the Texas Eye Research and Technology Center, says brown or amber lenses are recommended for athletes and the visually impaired, who desire contrast.
Color or lens density are not what protect the eye from sun damage. The degree of darkness, may have little or no effect, Bergmanson says, on what is important — ultraviolet radiation filtering capabilities.
Quality sunglasses provide protection from ultraviolet rays — specifically against wavelengths ultraviolet B and ultraviolet A.
“Exposure to ultraviolet ray radiation, which is cumulative over time and puts one at greater risk for developing eye and vision disorders, can be minimized,” Bergmanson says in a statement.
He points out the American National Standards Institute has two different standards for protection. A Class 1 UVR-blocking lens absorbs 99 percent of UVB and 95 percent of UVA rays, while a Class 2 lens filters out 95 percent of UVB and 70 percent of UVA rays.
Any lens claiming to provide UVR protection, Bermanson says, must at least meet the Class 2 standard.
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