Shatter proof spectacles may not be as safe as the wearers assume and could be a health hazard. Too many spectacles, sunglasses and sports and industrial eyewear have passed the safety standards, but yet may easily shatter.

The safest are the polycarbonate lenses which stood up well to rigorous tests carried out by the Johns Hopkins University in Bethesda, Maryland. But other supposedly shatter proof lenses fared less well.

Researchers are concerned that the American safety standards in particular ANSI Z80 and Z87 are too lax. The current test is to hit the lens with a ball travelling at just 11 mph, when a squash or tennis ball, for instance, could be travelling at 10 times that speed in real life (JAMA, 1997; 277:142-4).

Connection error. Connection fail between instagram and your server. Please try again
Written by What Doctors Don't Tell You

Explore Wellness in 2021