ECP Solution Center

Shedding Light on UV

Karl Citek, OD, PhD, FAAO

Karl Citek, OD, PhD, FAAO, is a professor of optometry at Pacific University in Forest Grove, Oregon, where he has been on faculty since 1994. Long interested in the effects of UV on vision and eye health, Dr. Citek published a paper on UV reflectance from No-Glare lenses in 2008.

What are some common misconceptions? “ECPs might THINK they are doing well when they provide lenses with UV-absorbing properties,” explains Dr. Citek. “However, those properties refer ONLY to UV occurring at the front of the lens.”

When thinking about UV protection, it's important to consider both UV that transmits through the lens as well as UV light that reflects off the lens surface—especially on the backside.

THE ISSUE

Today, lenses that claim 100 percent UV protection address only UV light transmission.

“Transmission deals only with UV light that passes through the lens at the front surface,” explains Dr. Citek, “whereas reflection deals with UV light that ‘bounces off’ the lens surface.

“With No-Glare technology,” adds Dr. Citek, “reflectance of visible light is significantly (and purposely) decreased, but UV reflectance can be increased well above that of an uncoated lens.”

So, why is backside UV reflection an issue? Says Dr. Citek, “UV can easily get to the eye around the lens. If the lens is large enough, especially with a flat base curve, UV can easily reflect from the back surface.”

Measures have shown that up to 50 percent of UV light reaches the eyes from the back and sides of the lens.

According to Dr. Citek, “This creates an invisible danger for patients. Since we can't see or feel UV, we are not aware that we are being exposed. [Even] on a cloudy day, most of the UV can get through. Also, we might think there is no danger when we face away from the sun. However, if the back surface of the lens is exposed to the sun, backside reflection can occur.”

ECPs have an opportunity and necessity to address this medical issue with their patients. “By providing full protection 365 days a year,” explains Dr. Citek, “ECPs have the potential of preventing short-term ocular injuries and discomfort, while also minimizing long-term complications.”

Dr. Citek says the ECP's recommendation needs to include lenses with 0 percent UV transmission, eyewear with good fit and contour to minimize UV coming around the lens or frame, and a PROPER No-Glare technology to minimize backside UV reflection.

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