BLINDSIDED: EMORY EYE SPECIALISTS DISCUSS LEADING CAUSES OF BLINDNESS

December 6, 1996

Media Contacts: Sarah Goodwin, 404/727-3366 - sgoodwi@emory.edu
Kathi Ovnic, 404/727-9371 - covnic@emory.edu
http://www.emory.edu/WHSC/

GLAUCOMA: EYE UNDER PRESSURE
CATARACTS: VISION BLOCK
DIABETIC RETINOPATHY: THE VANISHING FILM
MACULAR DENGENERATION: RUSTING OF THE RETINA

A regular visit to an eye doctor, a pair of glasses and maybe some contact lenses are probably all one needs to maintain good vision. That's all most people require. Yet the eye is a delicate window to view the world and it needs the utmost care to protect it from the elements of aging and disease. During an eye exam, the ophthalmologist looks for more than whether glasses are needed. Just like the eyes are a window into the soul, the eyes can be an indicator of systemic diseases such as high blood pressure or diabetes. Eye doctors therefore look for signs of glaucoma, cataract, macular degeneration or diabetic retinopathy. These four disorders cause more Americans to lose their sight than any other conditions.

GLAUCOMA: EYE UNDER PRESSURE

Glaucoma affects one in 25 Americans, blinding more than 5,000 individuals every year. It is a progressive disease that occurs when fluid (aqueous humor) and pressure build up in the eye and damage the optic nerve -- the nerve that collects visual images from the retina on the eye's back wall and transports them to the brain. Glaucoma victims have pockets of lost vision -- and vision loss can occur very slowly or, in rare cases, very quickly. African- and Native Americans, diabetics and those with family histories of the disease are most at risk. Black people are at four times more risk than white people.

"Glaucoma is very treatable in its early stages, when patients can keep the disease under control with daily medications and regular eye exams," says Reay Brown, M.D., director of the glaucoma service at the Emory Eye Center. Medications help control eye pressure by either slowing the eye's fluid production or improving drainage.

"We're now prescribing a very promising new eye drop, Xalatan," Dr. Brown says. "Patients like it because they only have to use it once a day. It uses a different mechanism than conventional drops to drain excess fluid and reduce eye pressure." The drop also has very few side effects. When drops or other medications no longer control the disease, or it's too late in the progression of the disease to prescribe them, specialists may recommend laser treatment. The laser surgically opens the eye's blocked fluid drain. In some patients, conventional surgery may be more appropriate.

"We use a scalpel to create a new channel or implant a special tube to help drain the fluid," Dr. Brown says. "We are investigating several new types of tubes that may be beneficial for certain patients."

Cataracts cause visual disabilities for five to 10 million Americans. The disorder may be caused by aging, smoking, heredity, trauma, radiation or certain drugs. Because cataracts occur when the eye's lenses gradually becoming cloudy, the chief symptom is a reduction in vision.

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CATARACTS: VISION BLOCK

Cataract sufferers also may experience double vision, become sensitive to glare, find that colors look yellowed or faded, observe spots that don't move when the eye moves, or see colored halos around lights.

Cataracts severe enough to hamper daily activities can be removed during an outpatient procedure. The ophthalmologist can implant an intraocular lens during the same procedure or prescribe contact lenses or glasses to replace the eye's lens.

Researchers at Emory Eye Center are using some of the most advanced and effective interocular and contact lenses available.

If the cataract is mild, glasses or contacts may be enough. No medications or dietary supplements to prevent or cure cataracts.

Eye Center molecular biologist Robert Church, Ph.D., is investigating the causes and prevention of hereditary and age-related cataracts. He has found that certain alterations in DNA, or genetic material, can cause production of an abnormal protein in the lens, leading to a predisposition to forming cataracts.

"By analyzing the patient's DNA alterations, we can find out what type of cataract the patient has and help determine the best method of treatment," he says.

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DIABETIC RETINOPATHY: THE VANISHING FILM

Diabetic retinopathy is a complication of diabetes, which can weaken the retina on the back wall of the eye and block, distort or blur vision. No one knows why diabetes sometimes causes abnormal blood vessels to form in the back of the eye. These new vessels can leak fluid into the retina or vitreous humor (the jelly that fills the eye) and contract, distort or detach the retina.

Retinopathy is strongly linked to duration, so people who have had diabetes for 15 years or more are at strong risk of developing this sight-stealing disease. It affects about 8,000 diabetics each year in this country.

"Our recent studies suggest that rigid control of diabetes dramatically reduces secondary complications, including eye, kidney, heart and vascular problems," says Thomas Aaberg, M.D., a leading retina surgeon and director of the Emory Eye Center.

"Rigid control means using an insulin pump or injecting insulin more than one time a day. Once diabetics have retinopathy, gradually instituting tight control will not reverse the disease, but may slow its progression. Retinopathy is preventable and very treatable with continuous medical treatment and a yearly exam by an ophthalmologist."

If vision is in jeopardy from retinopathy, Dr. Aaberg may recommend laser photocoagulation surgery, which seals the leaking vessels without an incision.

Emory participated in two National Institutes of Health-sponsored studies that showed the procedure can prevent vision loss by reducing abnormal blood vessel growth and decreasing the leakage of retinal vessels.

In rare cases, the vitreous becomes clouded with blood, and Dr. Aaberg may recommend cryotherapy, an outpatient procedure during which a freezing probe is applied to shrink the abnormal blood vessels. In the most severe cases, he may suggest a vitrectomy to remove the vitreous humor and replace it with a clear solution.

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MACULAR DENGENERATION: RUSTING OF THE RETINA

The macula is the center of the retina -- and the part of the back wall of the eye with the sharpest sight.

As people get older, the macula can break down, causing macular degeneration. It is the most common cause of blindness in people over age 50.

People with the disorder are unable to see fine details or objects in the center of their vision. Straight lines, like a door frame, can look crooked. Patients often will cock their heads sideways to see better. As with glaucoma and cataracts, early treatment is the key to preventing further vision loss from macular degeneration.

There are two kinds of macular degeneration -- dry and wet. Most people with the disease have the dry type, which has no cure. It causes a very gradual loss of vision. Wet macular degeneration happens when blood vessels on the macula leak, leading to the formation of scar tissue. This scarring damages the central retina and can cause blind spots or distort vision, much like warped film would change the image of a photograph. The best treatment for wet macular degeneration is laser surgery to seal abnormal blood vessels and halt the progression of the disease.

"We discovered in a recent study that patients treated with laser actually had better vision three years later than those patients who were not treated at all," says Paul Sternberg, M.D., director of Emory Eye Center's retina service. "There are a number of other therapies investigated here and at other centers that have not yet shown consistent, favorable results," he says. "These include external beam radiation, vitamins and the drugs interferon and thalidomide."

But he and his Eye Center colleagues remain optimistic about the treatment of macular degeneration. They are investigating retinal cell transplantation to replace damaged cells and a new laser surgery to remove drusen, or the age spots that can form on the macula in the early stages of the disease.

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