In honor of National Sunglasses Day, the answer to the question: Why do we wear sunglasses to begin with?

Reasons for wearing shades

Did you know that too much exposure to UV light raises the risks of eye diseases, including cataract, growths on the eye and cancer?

Strong exposure to snow reflection can also lead to a disease called snow blindness.

The American Academy of Ophthalmology says growths on the eye, such as pterygium, can show up in our teens or 20s, specifically in surfers, skiers, fishermen, farmers, or anyone who spends long hours under the midday sun or in the UV-intense conditions found near rivers, oceans and mountains.

Diseases of the eye can take years to develop, much like skin cancer, but each time we're out in the sun without protection, potential damage is added.

History of sunglasses 

In prehistoric times, Inuit peoples wore flattened walrus ivory glasses to block harmful reflected rays of the sun, but the earliest historical reference to sunglasses dates back to ancient China and Rome.

The Roman emperor Nero watched gladiator fights through polished gems, and in China, sunglasses were used as early as the 12th century. These sunglasses were made out of lenses that were flat panes of smoky quartz. While they didn't block harmful UV rays, they did protect the eyes from glare. Judges in ancient Chinese courts used them to hide their facial expression when they interrogated witnesses.

According to Glasses History, James Ayscough began experimenting with tinted lenses in spectacles around 1752. He believed blue-or green-tinted glass could potentially correct specific vision impairments. Glasses tinted with yellow-amber and brown were also a commonly prescribed item for people with syphilis in the 19th and early 20th century because one of the symptoms of the disease was sensitivity to light.

In the early 1900s, the use of sunglasses become more widespread, especially among Hollywood movie stars. The first inexpensive mass production of sunglasses began in 1929 when Sam Foster sold his sunglasses on the beaches of Atlantic City, New Jersey, under the name Foster Grant on the Boardwalk. 

Polarized sunglasses were first available in 1936, when Edwin H. Land, co-founder of Polaroid and inventor of inexpensive filters for polarizing light, a practical system of in-camera instant photography, began using his patented Polaroid filter when making sunglasses.