Sunglasses come with labels that tell you if they offer optimal UV protection. Look out for one of these three labels:
The “100% UV protection” label is self-explanatory. It shows that the sunglasses will block 100 percent of the sun’s harmful rays.
- Block both UVA and UVB rays
The “blocks UVA/ UVB radiation” label is more specific. It shows that the sunglasses block both UVA and UVB radiation.
UVA radiation makes up 95% of the UV rays that reach us. They can damage the retina and cause blurry vision. On the other hand, UVA radiation makes up 5% of the UV rays that reach us. However, they can damage the cornea and lens to cause eye sunburn and cataract development.
There are three types of UV radiation - UVC, UVB, and UVA. UVC is filtered by the atmosphere and does not reach the earth's surface. Only UVA and UVB reach us from the sun. So, if a pair of sunglasses blocks UVA and UVB radiation, they offer 100 percent UV protection.