The effect of sunglasses on ocular exposure to ultraviolet radiation.

Thirty-two pairs of inexpensive sunglasses were examined for their effectiveness in preventing ultraviolet radiation (UVR) from reaching the eyes. The transmission of UVB (290-310 nm) by all of the sunglass lenses was less than 2 per cent. However, in measurements performed with mannikins wearing the sunglasses, up to 14.1 per cent of the incident UVR passed through to the eyes. When the sunglasses were moved 6 mm from the forehead, the per cent reaching the eyes ranged from 3.7 to 44.8 per cent. Although sunglasses are somewhat more effective than untinted prescription eyewear in attenuating ocular exposure, the amount of attenuation is highly variable and depends mainly on their size, shape, and wearing position.