May 2, 2011

Sunlight and Eye Damage

By Peter Fries, M.D.
Eye Surgeons Associates

Printed articles in magazines, newspapers and medical journals over the last several years have been continually reminding us of the variety of health risks associated with sunlight exposure. Damage to eyesight from sunlight, or more specifically, ultraviolet light has been known for decades, with more recent information identifying specific eye diseases that may be caused or worsened by life-long ultraviolet light
exposure.

Most of us are familiar with “snow-blindness;” a temporary burn of the front surface of the eye from intense ultraviolet (UV) light exposure over a short time. Usually associated with reflected sunlight from snow or water, it is painful and irritating, but in one to two days the eye and sight are back to normal. This sunburn of the eye can be completely protected against with the use of sunglasses with ultraviolet filters, just like suntan lotion with UV blockers can prevent sunburn on skin. While this is the most commonly known eye condition associated with UV exposure, several other ocular conditions have a strong association with UV. These include cataracts, macular degeneration, pterygium, and eye cancers.

Cataracts are a thickening of the naturally clear focusing lens inside the eye. As the thickening increases, vision decreases and blurs. While surgery is highly successful at restoring vision related to cataracts, an increasingly active older population is requiring more cataract surgery to restore vision than in the past. Several studies suggest that UV exposure, smoking and oxidation may play a larger role in cataract formation than just plain aging. A study involving fisherman on the Chesapeake Bay found that those who wore sunglasses and a hat were 3 times less likely to develop cataracts than those who didn’t. Those that smoked were twice as likely to develop cataracts.

Macular degeneration, a slowly progressive deterioration of support cells in the center of vision, is becoming more common in the age group over 70. Age-related macular degeneration (AMD) is the leading cause of visual impairment for individuals age 50 and older. Much research has been done to identify the reasons for this increase and to clarify the causes of the disease. Two studies have shown an increased exposure to ultraviolet light increases the risk of this disease.

A pterygium is a fleshy growth of tissue onto the cornea, the clear front window of the eye that can grow over the center of vision causing permanent scarring and visual loss. Under the microscope when removed, one can see typical UV damage in these growths that is similar to changes seen in sun-damaged skin. Although it can be surgically removed, in 30% of cases re-growth occurs.

Melanoma is currently the 8th most common of all cancers with 32,000 new cases found each year. Occurring more commonly in lighter pigmented people, frequent severe sunburns as a child or teenager is a strong risk factor for the later development of this cancer. While melanoma is not common around the eye, basal cell carcinoma is with nearly 10,000 eyelid and eyebrow tumors removed each year in the United States. Here again the strongest risk factor for these cancers is long- term sun exposure.

What can one do to protect themselves from these conditions? Clearly many of these conditions are related to age which can’t be controlled. The factor that is within our control is protecting against excessive UV exposure from the sun. Good sunglasses with UV filters are the first line of defense. A hat with a wide brim will reduce UV light to the eye by up to 50%. Several brands of sun block with an SPF of 20 or more are made especially for use around the eyes to protect the delicate skin. Create good habits for your children now and for those who currently have these conditions, these measures may help to slow down the disease although strong proof of this is still lacking for many of the conditions mentioned. Hopefully, as more studies are completed, a better understanding of environmental causes will greatly reduce these conditions in the future.

BIO: Dr. Peter Fries, with Eye Surgeons Associates, is certified by the American Board of Ophthalmology and completed a fellowship in Ocular Oncology and Ophthalmic Plastic and Reconstructive Surgery. Dr. Fries practices at Eye Surgeons Bettendorf and Rock Island offices. For more information please visit our website at www.esaeyecare.com.