Sunglasses or sunglasses (often called shades) are protective glasses that are used to prevent damage or discomfort to the eyes from bright sunlight and high-energy visible light. They can also sometimes act as visual aids, because there are various kinds of glasses called glasses or glasses, which have colored, polarized or dark lenses. In the early 20th century, they were also known as "Sun cheaters" (liars are American glasses slang).

The American optometry Association recommends that sunglasses protect the eyes from ultraviolet (UV) and blue light, which can cause serious eye problems, as long as someone is in the sun. After some surgical procedures (such as LASIK), it must be used immediately, and it is recommended to use it in dusty areas for a certain period of time, and it is recommended to use it in front of the TV screen or computer display after leaving home and after LASEK. For a long time, sunglasses have been associated with celebrities and movie actors, mainly because of the desire to disguise their identity. Since the 1940s, sunglasses have become fashionable accessories, especially on the beach.

Sunglasses prevent excessive exposure to light, including visible and invisible components.

The most extensive protection is against UV radiation, which can cause short-term and long-term eye problems, such as photokeratitis, snow blindness, cataracts, winglike, meat and various forms of eye cancer. Medical experts advise the public on the importance of wearing sunglasses to protect the eyes from UV damage; in order to obtain adequate protection, they suggest that sunglasses reflect or filter 99% or more UVA and UVB light with a wavelength of up to 400 nm. Sunglasses that meet this requirement are usually marked "UV400.". This provides more protection than the widely used EU standard (see below), which requires that up to 95% of the radiation at 380 nm must be reflected or filtered out. Sunglasses are not enough to protect the eyes from direct damage, and they do not cause permanent damage to the eyes even during an eclipse. Looking directly at the Sun requires special glasses, which are called sunglasses. This kind of glasses can filter out the ultraviolet rays harmful to the eyes.