Sunglasses

Lore & Background

Since the 1930s, sunglasses have been a popular fashion accessory, especially on the beach. The American Optometric Association recommends wearing sunglasses that block ultraviolet radiation (UV) whenever a person is in the sunlight to protect the eyes from UV and blue light, which can cause several serious eye problems. Their usage is mandatory immediately after some surgical procedures, such as LASIK, and recommended for a certain time period in dusty areas, when leaving the house and in front of a TV screen or computer monitor after LASEK. Dark glasses that do not block UV radiation can be more damaging to the eyes than not wearing eye protection at all, because they tend to open the pupil and allow more UV rays into the eye.

Reader's Guide

The only way to assess the protection of sunglasses is to check for UV-blocking certification. For adequate protection, experts recommend sunglasses that reflect or filter out 99% or more of UVA and UVB light, with wavelengths up to 400 nm. Sunglasses that meet this requirement are often labeled as 'UV400'. Sunglasses are not sufficient to protect the eyes against permanent harm from looking directly at the Sun, even during a solar eclipse. Special eyewear known as solar viewers are required for direct viewing of the sun.

Did You Know?

• Since the 13th century, Inuit made and wore snow goggles of flattened walrus or caribou ivory with narrow slits to block almost all harmful reflected rays of the sun.
• The first sunglasses, made from flat panes of smoky quartz called Ai Tai (靉靆), meaning 'dark clouds,' were used in China in the 12th century or possibly earlier.
• In 1913, Crookes lenses were introduced, made from glass containing cerium, which completely blocked ultraviolet light.
• Polarized sunglasses first became available in 1936 when Edwin H. Land began experimenting with making lenses with his patented Polaroid filter.