Vehicle side windows offer little protection from sun’s rays: study

Beverly Hills, CA – Your vehicle’s front windshield can provide some protection from the sun’s rays, but its side windows? Not so much, according to a new study conducted by Boxer Wachler Vision Institute.

Researcher Brian Boxer Wachler measured ultraviolet A radiation outdoors, then measured it behind the front windshield and driver’s side window in 29 motor vehicles from 15 different manufacturers made from 1990 to 2014.

He found that, on average, the front windshields blocked 96 percent of UV-A radiation, which has been linked to an increased risk of skin cancer and cataracts. In contrast, side windows blocked an average of 71 percent of UV-A radiation. Only 14 percent of vehicles offered a high level of UV-A blockage – greater than 90 percent – from their side windows.

The lower protection from side windows may expose the left side of a driver’s face and left eye to more UV-A light. According to the study, this finding may explain, in part, the higher rates of cataracts in left eyes and skin cancer on the left side of faces.

It is unknown if people can lower their risk of skin cancer or cataracts by wearing sunglasses or driving in certain environments, Boxer Wachler said in the study.

The Centers for Disease Control and Prevention recommends wearing sunglasses and sunscreen to protect against UV rays, which can damage the skin in less than 15 minutes. Keep sun protection in your car, bag or child’s backpack, CDC advises.

The study was published online May 12 in JAMA Ophthalmology.