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UV400 protection is a feature in eyeglass and sunglass lenses that blocks all harmful ultraviolet (UV) light rays. Lenses with this rating provide the highest level of UV protection for your eyes. This feature is a clear coating that is applied to the lens or built directly into the lens material itself.
read more about uv400 protection in sunglasses ...The "400" in UV400 refers to 400 nanometers (nm). UV light rays have wavelengths from 100 to 400 nanometers. This includes all UVA and UVB rays, which are the two types that can harm your eyes. A lens with a UV400 rating blocks all light rays with wavelengths up to 400 nm, which means it provides 100% UV protection.
Long-term exposure to UV light can seriously damage your eyes. It can contribute to cataracts, macular degeneration, and growths on the surface of the eye called pterygium. Wearing sunglasses with UV400 protection is one of the best ways to protect the health of your eyes and the delicate skin around them.
It is important to know that the darkness of a sunglass lens has no effect on its UV protection. A dark lens without UV protection is actually very dangerous. The dark tint causes your pupil to open wider, which lets *more* harmful UV light into your eye. Always look for a label or sticker that specifically says "UV400" or "100% UV Protection."
It is a common myth that only tinted lenses can block UV rays. In reality, UV400 protection is invisible. Many clear prescription lenses, especially those made of polycarbonate or high-index materials, naturally block 100% of UV light due to the chemical properties of the plastic. This means your everyday clear glasses can offer the same UV400 safety as your darkest pair of sunglasses.
Yes. The UV400 rating is the standard for 100% protection, as it blocks all UV light waves up to 400 nanometers, which covers the entire spectrum of UVA and UVB rays.
Most new sunglasses will have a sticker on the lens or a tag on the frame that states their UV protection. An optical shop also has a device called a UV meter that can test your lenses in a few seconds to see if they provide full protection.
Usually, yes, but not always. Polarization is a separate feature that cuts glare. UV400 is a separate feature that blocks UV light. Most high-quality polarized lenses will include UV400 protection, but you should always check the label to be sure.
You should always buy sunglasses from a reputable source to be sure the UV400 claim is true. Your optician can show you sunglasses that are guaranteed to provide full protection. They can also test your current sunglasses to make sure your eyes are properly shielded from the sun's damaging rays.
Recommended Types of Sunglasses. American Academy of Ophthalmology. https://www.aao.org/eye-health/glasses-contacts/sunglasses-recommended-types. Accessed April 7, 2026.
Tips to Stay Safe in the Sun From Sunscreen to Sunglasses. U.S. Food and Drug Administration. https://www.fda.gov/consumers/consumer-updates/tips-stay-safe-sun-sunscreen-sunglasses. Accessed April 7, 2026.
What Is UV 400 Protection on Sunglasses? All About Vision. https://www.allaboutvision.com/eyewear/sunglasses/lenses/uv-400-protection-mean/. Accessed April 7, 2026.
How to Choose Sports Sunglasses. American Academy of Ophthalmology. https://www.aao.org/eye-health/glasses-contacts/how-to-choose-sports-sunglasses. Accessed April 7, 2026.
Nonprescription Sunglasses Guidance for Industry. U.S. Food and Drug Administration. https://www.fda.gov/regulatory-information/search-fda-guidance-documents/guidance-document-nonprescription-sunglasses-guidance-industry. Accessed April 7, 2026.