Most people understand the link between ultraviolet (UV) radiation and skin cancer. Many are, however, less aware of the connection between UV radiation and eye damage. With increased levels of UV radiation reaching the Earth’s surface, largely due to the ozone layer depletion, it is important to take the necessary precautions to protect your eyes.
To brush up on your general knowledge of UV: UV light is electromagnetic radiation with a wavelength shorter than that of visible light (<400nm). UV rays are invisible to the human eye. UV light is categorized as UVA, UVB & UVC. The ozone layer blocks 97-99% of this radiation from reaching the Earth. UV radiation can also be given off by artificial sources like welding machines, tanning beds and lasers.
Factors influencing UV levels include: Geographic location (greater in tropical areas near the Earth’s equator); altitude (greater at higher altitudes); time of day (peaks between 10am and 2pm) and setting (UV levels are greater in wide open spaces, especially when highly reflective surfaces are present eg snow, sand and water). Another factor to consider is that certain medications eg Tetracycline, sulfa drugs, oral contraceptives, diuretics and tranquilizers, can increase your body’s sensitivity to UV radiation. Surprisingly, cloud cover does not affect UV levels significantly. Your risk of UV exposure can be quite high even on overcast days.
Small amounts of exposure to UV light are recommended as UVB radiation induces the production of Vitamin D in the body. Vitamin D is necessary for normal functioning of the nervous system as well as for bone growth and maintenance of bone density. Too much exposure to UV light, however, will have detrimental effects. UVB causes premature aging of the skin, sunburn and some types of skin cancer.
Spending long hours in the sun without eye protection also increases your chances of developing eye diseases. UVB damage to the eyes is also cumulative, so it’s never too late to start protecting your eyes.
UV related eye diseases include:
- PHOTOKERATITIS – This is a painful inflammation of the cornea caused by extreme exposure to UV radiation (aka corneal sunburn). Symptoms include red eyes, a foreign body sensation, extreme sensitivity to light and excessive tearing. The effects usually disappear within a few days but may lead to further complications later in life
- CATARACTS – This is a loss of transparency in the lens of the eye causing vision to become cloudy and blurred. If left untreated, cataracts can lead to blindness.
- PINGUECULUM – A yellowish, slightly raised lesion that forms on the surface tissue of the white part of your eye. They may cause the eye to become red, irritated and inflamed.
- PTERYGIUM – A non-cancerous overgrowth of the conjunctiva on to the cornea. Pterygia may cause vision to become distorted and require surgery to be removed
- RETINAL DAMAGE – UV rays may play a role in the development of macula degeneration. This damage is not reversible.
- SKIN CANCER around the eyelids – Basal cell carcinoma is the most common type of skin cancer to affect the eyelids. In most cases, lesions occur on the lower lid but they can occur anywhere on the eyelids, in the corners of the eye or under the eyebrows.
Guidelines for protection:
- The greatest amount of UV protection is achieved with a combination of sunglasses that block 100% of UVA and UVB rays; a wide-brimmed hat; and for those who wear contact lenses, UV blocking contacts.
- Not all sunglasses block 100% of UV rays. Classic Eyes will be able to best advise you on your options.
- Close fitting, wrap-around frames provide the best protection because they limit how much stray sunlight reaches your eyes from the sides and above.
- Larger frames will also help shield as much of the delicate tissues and skin around your eyes as possible.
- Remember to wear sunglasses even when you’re in the shade. Your eyes will still be exposed to reflected UV rays from buildings, roads and other reflective surfaces.
- Children and teenagers should also be wearing UV eye protection as they typically spend more time in the sun than adults. (In fact, nearly 50% of our lifetime exposure to UV rays may occur by age 18)
- UV absorbing contact lenses help protect against the transmission of UV radiation to the cornea and into the eyes. The Acuvue® range of contact lenses offer the highest level of UV blocking available.
- However, UV absorbing contact lenses are NOT substitutes for sunglasses because they do not completely cover the eye and surrounding areas. You should continue to use 100% UV absorbing sunglasses. Ask your eye care professional at Classic Eyes for more information.
So, SLIP on a pair of sunglasses, SLOP on some sunscreen, SLAP on a cap and head outdoors. Have fun in the sun all summer long, confident that you are protected against the ravages of UV rays.