Sunglasses provide good protection against the sun’s ultraviolet (UV) rays, long-term exposure to which is known to damage the eye’s surface and internal structures. Should you rush out to buy an expensive pair of sunglasses with dark lenses? The answer is “not necessarily.” The fact is that the ability to block UV light is dependent on neither the price nor the darkness of the lens. The standards and labeling regarding UV protection are voluntary, which means that price does not guarantee quality. And while plastic and glass lenses both provide a degree of inherent protection, it is the lens’ coatings that make all the difference. Sunglasses with labels that claim to block 99-100% of UV rays provide the best protection.Sunglasses with labels that indicate "UV absorption up to 400nm" offer 100% UV absorption. The sun can damage your eyes just like it can damage your skin.