You probably know that too much exposure to the sun’s ultraviolet (UV) rays can cause sunburn and skin cancer. But did you know UV can also harm your eyes? Extended exposure to the sun’s UV rays has been linked to significant eye problems, including cataracts, macular degeneration, pingueculae (excess growth of conjunctiva tissue), pterygium (excess growth of conjunctiva tissue onto the cornea) and photokeratitis (sunburn of the cornea).
To protect your eyes from harmful solar radiation, you should wear sunglasses that block 100 percent UV whenever you are outdoors in daylight. Your eyes need protection even on cloudy days because UV rays can penetrate cloud cover. Sunglass frames with a close-fitting wraparound style provide the best protection because they limit how much sunlight reaches your eyes from all sides.
While many people refer to ultraviolet radiation as UV light, this term is technically incorrect because you cannot see UV rays. Ultraviolet radiation is invisible to our sight.
There are three categories of UV radiation. UVC is the highest energy, short-wavelength UV rays and potentially could be the most harmful to your eyes and skin. Fortunately, the atmosphere’s ozone layer blocks virtually all UVC rays. But this means that the depletion of the ozone layer potentially could allow high-energy UVC rays to reach the Earth’s surface and cause serious UV-related health problems.
UVB rays have slightly longer wavelengths and lower energy than UVC rays. These rays are filtered partially by the ozone layer, but some still reach the Earth’s surface. In low doses, UVB rays stimulate the production of melanin (a skin pigment), causing the skin to darken causing a suntan. But in higher doses, UVB rays cause sunburn that increases the risk of skin cancer. UVB rays also cause skin discolorations, wrinkles and other signs of premature aging of the skin. Overexposure of the sun’s UVB radiation is also associated with a number of eye problems, including pingueculae, pterygium and photokeratitis.
Spending time outdoors without UV eye protection increases the risk of eye damage. UV exposure is highest near the equator, at higher altitudes and during midday hours (10 am to 2 pm). Open areas with reflective surfaces like water, snow or sand can significantly boost UV exposure—snow and water can nearly double it. Additionally, some antibiotics can heighten sensitivity to UV radiation.
In summary, to best protect your eyes from the sun’s harmful UV rays, always wear good quality sunglasses when you are outdoors all year. Look for sunglasses that block up to 100% of all UV rays. Your eye care professional can help you choose the best sunglasses for your needs.
