Sunglasses UV Protection

UV blocking glasses protecting eyes and lids

Overview

Sunglasses are tinted eyewear that reduce the brightness of visible light and, when appropriately manufactured, block ultraviolet radiation. Ultraviolet exposure is linked to photokeratitis, a painful sunburn of the cornea known as snow blindness in snowy environments, and to long term conditions including cataract, pterygium, pinguecula, and skin cancers of the eyelids, and it has been studied as a possible contributor to macular degeneration. Standards in various regions, such as ANSI Z80.3 in the United States, EN ISO 12312 in Europe, and AS NZS 1067 in Australia and New Zealand, define ultraviolet transmittance limits and lens categories. Lens darkness and ultraviolet protection are separate properties, and dark lenses without ultraviolet filtering may increase exposure by allowing the pupil to dilate. Polarized lenses reduce glare from reflective surfaces such as water and roads, while wraparound frames limit light entering from the sides. Lens color affects contrast and color perception. Slit goggles carved from bone, antler, or wood, used by Inuit and other Arctic peoples for centuries, are an early form of eye protection against glare.