-The EYE Digest -
Sunlight and the Eye: How UV Light can Damage the Eye and How to Prevent It
You feel it in the air, the rains of March and April are gone, the chilly winds of winter are long past. As you open the door to venture outside, you're hit a with a whiff of that sweet freshly cut grass smell. Your senses become attuned to the warmth radiating down from the sky above.
It is officially summer.
Beach days, shorts and sandals, bike rides, and cruising down the highway with the top down are just a few of the activities you look forward to with this sudden change in weather. As you step outside into the sunshine, you are swept with memories: public service announcements about skin cancer, sunscreen commercials, sunglasses on billboards. And those two letters they always mention. What were they? U-V. That's right. But what does it all mean?
When we bask in sunshine we are exposed to Ultraviolet light or UV for short. While sunlight does play an important part in activating vitamin D, it is damaging to DNA in the skin.
Light initiates a reaction between two molecules of thymine, one of the bases that make up DNA. A thymine dimer is formed from this reaction. The body is normally very efficient at repairing this dimer (damage), but if too many of these occur, the likelihood of a mistake in repair increases. Thus, these mistakes as a result of overexposure to sunlight can result in sunburning, and chronic exposure can lead to something far more serious, skin cancer.
In the state of California, skin cancer is the most common type of cancer and is classified as an epidemic by the California Department of Health Services.
In addition to the effects on the skin of the body, UV light can damage the eyes in a variety of ways:
-Eyelids - skin cancer
-Conjunctiva (white part of the eye) - pinguecula/pingueculitis
-Cornea (clear part of the eye) - pterygium
-Lens - cataracts
-Retina - macular degeneration/solar retinopathy.
Eyelids and Skin Cancer
Just like the skin on your body, eyelid skin is susceptible to the same types of damage that can be incurred with UV light. Be on the lookout for any suspicious looking spots or growths on your eyelids, and tell your doctor right away if you notice anything new or out of the ordinary. A good self test to run through when examining a lesion, mole, freckle or skin tag is the ABCDE rule:
- Asymmetry – does the lesion look “equal” on both sides?
- Borders – are there clearly defined borders/outlines to the lesion?
- Color – is the color of the lesion uniform?
- Diameter – is the diameter of the lesion less than 6mm?
- Evolving – is the lesion staying the same?
If you answered “No” to any of these questions, then it may be pertinent to have the lesion checked by health care professional!
Pinguecula and pterygium are conditions related to UV damage that can affect the front of the eye. Pinguecula present as a raised bump with a clear blister-like appearance on the conjunctiva (white part) of the eye. Sometimes, these bumps can become inflammed and result in a condition called pingueculitis. Pingueculitis can be treated and is something we frequently see in our office.
Pterygium occurs when a pinguecula grows onto the cornea (clear part of the eye). Pterygium can present a problem not only cosmetically, but visually as the pterygium can induce astigmatism (change your glasses prescription). If a pterygium grows far enough on the cornea, it can actually begin to block vision! Surgical intervention is needed if it progresses to this stage.
In the future we will have a whole EYE Digest series on cataracts. However, as a precursor to that, it is important to note that cataracts occur because of free radical damage to the lens of the eye. Free radicals can occur from within the body, but UV light also plays a large role in damaging the lens of the eye and leading to cataracts long term.
Lastly, the retina (back of the eye) can be damaged by UV light. Studies have shown that exposure to UV in the long term is associated with increased incidence of macular degeneration. Solor retinopathy is damaging of the retina that is associated with directly gazing at the sun.
So how do protect our eyes against all these conditions associated with sunlight and UV?
The answer is simple. Sunglasses!
Whether your prefer an Oakley wrap around, a Maui Jim aviator, or a Ray Ban wayfarer, make sure to wear your sunglasses when you are outside at all times. A lens with UV protection protects all structures of the eye as well as the eyelid from sun damage. The lens works by acting as a barrier between UV light and the biological components of the eye, thus protecting the eye.
Polarization in sunglass lenses provides an additional benefit by reducing glare and reflection. Polarization can be especially useful when participating in ocean/lake related activities or on the beach since they help cancel out uncomfortable sunlight reflections off of water.
Additionally, certain brands of contact lenses have been adding UV protection to the composition of their lenses. This can provide an added level of protection, but is never a substitute for sunglasses.
If you have any additional questions on how UV light can affect the eye or what sunglasses are best for you, don't hesitate to either contact us or stop in our office. Our doctors are happy to discuss UV light and the eye in more detail with you and our experienced opticians would love to help you find a pair of sunglasses that both match your own unique style and help protect your vision from the sun's harmful rays.
-Dr. Aaron Neufeld