Ultraviolet (UV) blocking contact lenses are designed to absorb harmful UV radiation before it reaches the eyes. Prolonged sun exposure poses a significant risk to ocular health. These lenses offer an added layer of defense against UV light, which can harm the eye. Understanding how these lenses function clarifies their role in protecting vision.
How UV Blocking Contacts Provide Protection
UV-blocking contact lenses incorporate a specific UV-blocking agent, such as a dye or an absorbing substance, into the lens material. This integration means the protective properties are permanent and will not diminish or wear off, unlike a surface coating. The sun emits UVA and UVB rays, both of which can harm the eyes. UVA rays typically penetrate deeper into the eye, while UVB rays are stronger and largely absorbed by the cornea and lens.
The United States Food and Drug Administration (FDA) classifies UV-blocking contact lenses into two categories based on their absorption capabilities. Class 1 lenses offer the highest level of protection, blocking more than 90% of UVA radiation (316-380 nm wavelengths) and over 99% of UVB radiation (280-315 nm wavelengths). Class 2 lenses provide a substantial level of protection, filtering more than 70% of UVA and over 95% of UVB radiation.
Health Advantages of UV Protection
Reducing UV exposure offers several long-term health advantages. Chronic exposure to UV radiation is a known risk factor for the development of cataracts, which is a clouding of the eye’s natural lens that can lead to blurred vision. Protecting the eyes from UV rays can reduce the likelihood of developing this condition. Another condition linked to prolonged UV exposure is pterygium, a fleshy growth on the white of the eye that can extend onto the cornea and interfere with vision.
UV protection also helps prevent acute issues like photokeratitis, often described as a sunburn of the cornea. This painful condition results from intense UV exposure and may cause symptoms such as pain, redness, light sensitivity, and temporary blurred vision. UV-blocking contact lenses can help shield the corneal and conjunctival stem cells, which are susceptible to damage from tangential and temporal UV rays.
Are UV Blocking Contacts Enough?
While UV-blocking contact lenses provide an important layer of defense, they do not offer complete eye protection. These lenses only cover the cornea and pupil, leaving surrounding areas like the eyelids, conjunctiva, and sclera exposed to UV radiation. These uncovered areas remain vulnerable to sun damage, including growths like pinguecula and skin cancers around the eyes.
UV-blocking contact lenses are a supplementary form of protection, not a standalone solution. Eye care professionals recommend combining UV-blocking contact lenses with comprehensive UV-blocking sunglasses (UV400 or 100% UV protection) to shield the entire eye and surrounding skin. Wearing a wide-brimmed hat further enhances protection by reducing direct and peripheral UV exposure to the eyes and face.