The sun emits invisible ultraviolet (UV) radiation, categorized as UVA and UVB rays, which poses a significant risk to eye health. Unprotected, cumulative exposure to both types of radiation is linked to serious eye conditions, including cataracts and photokeratitis (corneal sunburn). UVA rays penetrate deep into the eye, potentially harming the retina, while UVB rays are primarily absorbed by the cornea and lens. Contact lenses can offer a valuable layer of defense against this threat, but this protection must be specifically manufactured into the lens material, as not all contacts provide this feature.
UV Protection Standards in Contact Lenses
UV blockage in contact lenses is not an inherent property of all materials; it is an added feature requiring specialized UV-absorbing compounds within the lens. Manufacturers adhere to standardized classifications to indicate the level of protection provided. These standards delineate two main classes of UV-blocking lenses based on the percentage of ultraviolet light they filter.
The highest rating is Class 1, which represents the strongest defense against solar radiation. Class 1 lenses are designed to block at least 90% of UVA rays and 99% of UVB rays from reaching the cornea and the interior of the eye. This level of protection is generally recommended for individuals who spend considerable time outdoors or are exposed to high-UV environments.
The second tier of protection is Class 2, which still offers a substantial barrier. Class 2 lenses are rated to filter out at least 70% of UVA radiation and a minimum of 95% of UVB radiation. Both classifications significantly reduce the amount of harmful energy entering the eye compared to non-UV-blocking lenses.
The distinction between the two classes is primarily based on the amount of longer-wavelength UVA light that is successfully blocked. While both are highly effective against UVB rays, the Class 1 standard ensures a greater percentage of the deep-penetrating UVA is stopped. This protective feature is integrated into the material and does not affect the clarity or quality of the wearer’s vision.
Physical Limitations of Contact Lens Coverage
Even with the highest Class 1 rating, contact lenses cannot serve as a complete substitute for high-quality sunglasses. This limitation stems from the physical area of the eye that the lens is designed to cover. A contact lens sits directly on the cornea and covers the pupil, providing excellent protection to the underlying structures like the lens and retina.
However, the lens does not extend to cover the entire ocular surface or the surrounding delicate tissues. Structures such as the conjunctiva, the limbus, and the sclera (the white part of the eye) remain exposed. Additionally, the skin on the eyelids and the surrounding orbital area are completely unprotected by the contact lens.
Light can enter the eye from the sides, above, and around the edges of the contact lens, known as peripheral light exposure. This exposure can contribute to the development of growths on the eye’s surface, such as pterygium and pinguecula. Furthermore, the sensitive skin around the eyes is vulnerable to premature aging and skin cancers. Because of these coverage gaps, regulatory bodies do not classify UV-blocking contact lenses as a primary or complete form of sun protection.
Finding and Selecting UV Blocking Lenses
Identifying contact lenses with UV protection requires checking the product packaging or consulting with an eye care professional, as the feature is not universal. Look specifically for clear labeling that states the lenses are “UV absorbing” or “UV blocker” and indicates the protection class. The inclusion of UV protection does not alter the prescription or the lens fit, making it an added benefit available in many types of disposable lenses.
When speaking with an optometrist, you should specifically request a prescription for UV-blocking contact lenses. Standard prescriptions may not automatically include this feature, so making a clear request is necessary. Your eye care provider can recommend a lens that matches your vision correction needs while also meeting the Class 1 or Class 2 UV standard. Since the UV-blocking compounds are colorless, they do not tint the lens or change the appearance of your eyes.
Selecting a lens with a UV classification is a proactive step toward protecting the internal structures of the eye from long-term damage. It provides a foundational layer of protection that works consistently throughout the day, even in environments where sunglasses might be forgotten or impractical. By combining UV-blocking contacts with wraparound sunglasses, you create the most comprehensive shield against both direct and peripheral sun exposure.