The light spectrum encompasses the entire range of radiation, which can be grouped into distinct bands or regions. From the shortest to the longest wavelengths are: gamma radiation, X-ray radiation, ultraviolet (UV) radiation, visible light, infrared (IR) radiation, microwave radiation, and radio waves. Each of these categories can be further subdivided.1
Ultraviolet (UV) radiation comes from the invisible part of the light spectrum. Although we can’t see it directly, UV-A (315 to 400nm) and UV-B (280 to 315nm) light can damage ocular tissues, including the cornea, conjunctiva, lens, and retina. The damage slowly accumulates over time and is irreversible once it occurs.2
I proactively talk to every one of my patients about UV protection because it's so important to ocular health. Busting myths about UV exposure is a key part of educating our patients about how to care for their eyes. UV protection may be a more obvious topic in Southern California, where I practice, but it’s important no matter where you live.
UV exposure and ocular health
Conditions associated with UV exposure include photokeratitis (similar to a sunburn of the cornea), ocular melanoma, pinguecula, pterygium, and accelerated development of cataract and macular degeneration.3 The lens absorbs UV as a way of protecting the retina, but UV causes alterations in lens proteins that contribute to the yellowing and thickening of the lens that we know as cataract.3
In sunny climates and those closer to the equator, the high degree of UV exposure, especially for people who spend a lot of time on the water, such as fishermen and surfers, can cause changes in conjunctival tissue and pigmentation similar to freckles on the skin.4
In these populations, pinguecula and pterygium are common, and these in turn can contribute to aberrated vision, dry eye, and irritation, as well as an unwelcome cosmetic appearance.3 An additional reason UV exposure can result in the formation of pinguecula and pterygium is damage to the limbal stem cells.5
Case in point, the cornea is highly susceptible to UV irradiation due to its transparency and curved shape, contributing to a peripheral light-focusing effect in which UV irradiation is intensified 20-fold at the nasal limbus.5
Opt for layers of sun protection
UV-blocking contact lenses are a great, always-on form of additional eye protection. They filter UV exposure to all tissues from the anterior ocular surface to posteriorly, i.e., cornea, limbal stem cells, iris, lens, etc.
However, keep in mind that some portions of the eye plus the ocular adnexa are still exposed, thus proper sunwear needs to be stressed, including but not limited to a wide-brimmed hat, sunglasses, and of course skin protection.6 Patients should also be counseled to wear sunglasses and a hat to protect the sclera, parts of the conjunctiva, and the skin around the eyes.6
Although all spectacle lenses contain a UV filter, many contact lens brands do not. UV filtering in soft contact lenses can be a complicated process, as additional polymers need to be added and alterations in the curing process have to be optimized.7,8
As such, for a contact lens to add this feature, a significant change would need to occur on the manufacturing floor, and an update to the FDA approval would be required.8
Comparing UV filtering in contact lenses
Lenses that also filter a portion of the blue/violet visible light spectrum (in addition to UV) can be even more difficult to cure. I typically recommend that my patients wear contact lenses with Class I UV filtering for maximum protection, meaning that they filter at least 90% of UV-A and 99% of UV-B.9 Several contact lens brands meet the requirements of this class.
UV-filtering contact lenses:9-17
- Class 1: Blocks 90% UV-A and 99% UV-B radiation
- Examples include:
- Johnson & Johnson Vision: ACUVUE OASYS, ACUVUE OASYS 1-Day, ACUVUE OASYS MAX 1-Day, and ACUVUE VITA
- Alcon: TOTAL30, DAILIES TOTAL1, DAILIES TOTAL1 for Astigmatism, PRECISION1, PRECISION7
- CooperVision: Avaira Vitality
- Examples include:
- Class 2: Blocks 70% UV-A and 95% of UV-B radiation
- Examples include:
- Johnson & Johnson Vision: 1-DAY ACUVUE MOIST
- Bausch+Lomb: INFUSE One-Day, Biotrue ONEday
- CooperVision: Clariti 1-Day, MyDay
- Examples include:
Among these, I frequently recommend the ACUVUE OASYS MAX family of lenses, which filter 100% of UV-A and 99.9% of UV-B rays—making them the contact lenses with the highest level of filtering.18 ACUVUE OASYS MAX lenses also filter 60% of the light at the blue-violet end of the spectrum, which is the light that causes the most light scatter and glare.18
Figure 1: Demonstration of the effective filtering of UV light utilizing a large photochromic lens with several different contact lenses placed on top. The ACUVUE OASYS MAX lens effectively filtered both UV-A and UV-B radiation very effectively, as demonstrated by the clearer circular area on the lower left where the lens prevented the photochromic lens from darkening.
Figure 1: Courtesy of Jennifer Chinn, OD.
5 myths about UV protection
There are many myths regarding the best ways to protect your eyes from UV rays. We can be of service to our patients in helping them understand the realities of UV exposure and by providing contact lens options that fit into a comprehensive sun-protection strategy.
1. Sunglasses will fully protect my eyes
Most styles of sunglasses don’t fully block UV rays because they let peripheral light rays in around the sides of the frames.19 Moreover, people often remove their sunglasses in the water or at times when the sun is less intense.
2. Darker sunglasses provide more sun protection
A darker tint helps with light sensitivity, but it tells you nothing about the degree of UV protection. Spectacle lenses and car windows have high levels of UV protection even when they are completely untinted.20 Similarly, sunglasses with a variety of tints can provide excellent UV filtering—or can be of poor quality.
For example, very dark-tinted lenses can actually be harmful if they don’t fully block UV because your pupils may dilate, letting more UV reach internal structures of the eye. Always look for sunglasses labeled as providing "UV400" or "100% UV protection.”21
3. I only need UV protection on hot summer days
UV exposure is related to light, not temperature. UV rays are present year-round and in a variety of climates.
As UV exposure increases at higher altitudes, and when reflected off snow, winter sports like skiing actually put people at high risk of UV exposure.22 Further, individuals who live closer to the equator experience greater UV exposure.
4. Cloudy days have a low risk of UV exposure
Even on cloudy days, there can still be significant UV exposure. According to the Environmental Protection Agency, clear skies allow virtually 100% of UV to pass through, scattered clouds transmit 89%, broken clouds transmit 73%, and overcast skies transmit 31%.23
An easy way for patients to test this for themselves is to pay attention to someone wearing photochromic lenses. Such lenses are activated by the amount of UV in the environment, so they will darken outside on cloudy days but not inside a car with a UV-protecting windshield.
5. The greatest UV risk is at midday
While it is true that the greatest risk to the skin is between 10:00am and 2:00pm, when the sun is directly overhead, the eyes are somewhat shaded by the brows and facial bones. Consequently, UV exposure for the eyes can actually be most intense in the morning and mid-afternoon when light enters the eye at a more oblique angle.24
Key takeaways
- Photokeratitis, ocular melanoma, pinguecula, pterygium, and accelerated development of cataract and macular degeneration are associated with ocular UV exposure.3
- UV-filtering contact lenses can provide an extra layer of protection against UV damage.
- Class 1 UV-filtering lenses provide the most protection. Of these, the ACUVUE OASYS MAX family of lenses filter 100% of UV-A and 99.9% of UV-B.18
- UV protection is needed all day and year-round, even on cool or cloudy days.22
Conclusion
By reinforcing the importance of year-round UV protection, we can help our patients safeguard ocular structures that are vulnerable to cumulative, irreversible damage.
Educating patients about the limitations of sunglasses alone and the pervasive nature of UV exposure empowers them to make informed decisions about comprehensive protection.
As primary eyecare providers, our role in dispelling myths and recommending evidence-based solutions is essential to reducing the long-term burden of UV-related ocular disease.
