November 24, 2014

Sight Savers

Age-related diseases of the eye, like cataracts and macular degeneration, traditionally have been initial steps down a slippery slope of ever-worsening vision. But as the baby boomer generation ages, more research dollars are pouring into finding better ways to prevent and care for diseases of aging eyes, resulting in a better outlook for the future.

Fighting Macular Degeneration

The most common form of this disease is age-related macular degeneration (AMD). "One-third of people over 65 are going to show some form of macular degeneration," says Dr. David C. Brown, medical director of the Eye Centers of Florida's main clinic in Fort Myers.

The disease comes in two forms. Dry AMD is the more common, accounting for about 90 percent of AMD cases. For reasons scientists still don't understand, the macula, which is located in the center of the paper-thin retinal tissue lining the back of the eye, begins to deteriorate. Since the macula is made up of light-sensing cells that help produce central vision (as opposed to peripheral), initial symptoms include blurred central vision and possibly a blind spot. Usually there is no pain.

In wet AMD, dry AMD worsens, causing blood-vessel fragility that leads to the leakage of fluid and blood under the macula. This can result in rapid vision loss. In fact, though it accounts for only 10 percent of AMD cases, wet AMD is responsible for about 90 percent of all blindness from AMD, according to the National Eye Institute of the National Institutes for Health.

Traditional treatment for wet AMD has involved sealing the leaking vessels with a concentrated laser beam, but this often resulted in what Dr. Joseph Walker of Retina Consultants in Naples calls "a limited victory." Subsequent damage to the retina could lead to permanent blank areas in a patient's vision.

A new product called Visudyne has been under review for the past year and a half, with Walker being one of the principal investigators in the study's Southwest Florida hub. Visudyne collects in these abnormal blood vessels, allowing for more specificity with a lower-power laser beam, with less potential damage to surrounding tissue. "It gives you much greater hope that you can preserve more usable sharp central vision," says Walker.

More hope for AMD patients is provided by an experimental, genetically engineered compound known as a VEGF inhibitor. With a trade name of Rufab, the compound showed signs of slowing growth of abnormal blood vessels during a limited pilot study. Rufab is currently going through the FDA approval process, and may soon move into wider clinical trials.

One of the risks with any bleeding under the retina is that clots could form and destroy the retina in that area. Another genetically engineered compound, TPA (traditionally used as a general clot buster, according to Walker), has begun to be used to break up clots in the eye and help restore vision-if the problem is caught early enough.

"There is practically no effective treatment" to control AMD, particularly the dry variety, notes Brown. But the Eye Centers of Florida participated with a company called Oculogic in a study involving filtering the blood to improve poor circulation to the retina-which some theorize may be why macular degeneration occurs. Larger molecules of cholesterol and other substances are filtered out of the bloodstream, which improves circulation in the body in general, but notably in the eye. Though promising, the project ran out of funding.

New Surgeries for Cataracts

Once upon a time a cataract diagnosis was a gloomy one-little could be done to remove the cataract and restore vision. But now, about 1.5 million cataract surgeries are performed each year, according to the National Eye Institute. It's one of the most common surgeries performed in the United States, and is safe and effective.

The lens of the eye, which focuses light on the retina for relay to the brain, is made up mostly of water and protein. As the eye ages, these proteins may clump together, clouding the area of the lens, possibly growing larger over time, and forming a cataract.

More than half of all Americans age 65 and older have cataracts, according to the NEI. As it grows, the cataract may cause lights to glare or take on a halo effect, cloud vision, affect night vision, and dim perception of colors. Doctors will often not treat the cataract until vision is occluded enough to impact everyday activities like driving or reading. (Although the NEI is researching drugs to control cataracts so surgery will not be needed, these substances are not yet commercially available.)

A new type of surgery involving smaller incisions in the cornea and a "foldable" lens implant has been widely successful in the last two years in treating the common affliction. Sound waves break the cataract up into smaller pieces (about the size of the tip of a pen) so it can be removed through the incision, and the artificial lens is bundled up, inserted, and "unfolded" over the eye.

"Technology has become so fantastic, it's really become easy," says Walker. "A quick in-and-out, and you go back to what you were doing the next day." Often the incision doesn't even require stitches after the lens has been inserted. As an added bonus, the lens, which is custom-made for the patient's prescription, can also alleviate the need for glasses or contacts.

Controlling Glaucoma

Glaucoma, in which fluid normally present in the eye builds up and increases pressure inside the eye, is a leading cause of blindness in the United States, the NEI reports. The disease has no symptoms in its early stages. Gradually failing side vision may lead to a narrowed field of vision and eventually blindness if untreated.

Glaucoma cannot be cured, but can usually be controlled with medications that lower eye pressure (eye drops or pills), laser surgery, or traditional surgery. Advances in treatment have been slow, partly because scientists still don't fully understand the causes of glaucoma.

Laser beams can be used to open up drainage channels in the eye, with limited success, and surgery has recently begun to be performed in conjunction with substances called antimetabolites-usually used for treating cancer patients-to reduce pressure and help keep eye tissue from scarring.

New genetic tests can help predict the occurrence of certain inheritable forms of the disease, according to Brown, and prediction may be the best treatment for now. "It's important to get glaucoma treatment done before there is damage," he says.

Keeping a Watchful Eye

One of the smartest things the older patient can do to care for aging eyes is to have regular eye appointments to monitor eye health and catch any problems early. Once a year patients should have their eyes dilated so doctors can check for disease, and to create a health history so that the doctor can notice changes easily.

One exciting new tool in monitoring the health of the eye is the "scanning laser," which, with the help of computers, develops a diagram of the nerves inside the eye, giving doctors a picture of exactly what is occurring within the eye and allowing detection of early signs of damage. The laser scan is usually covered by insurance, Brown says, and offers doctors and patients a huge advantage over traditional means of detection.

Another ongoing NEI study focuses on prevention and care for the eye to ward off problems. Results from the nearly 5,000 participants in the Age-Related Eye Disease Study (AREDS), in progress since 1992, show that supplements of certain antioxidants, like vitamin E, vitamin C and beta carotene, in conjunction with zinc, can lower high-risk patients' chances of developing AMD by 25 percent.

Other risk factors are controllable-smoking and excessive sun exposure are thought to factor into cataract formation, for example-and changing these habits as early as possible may lower one's risk for eye problems later.

Eye Talk

In conjunction with the Retina Consultants of Southwest Florida, the Schepens Research Institute of the Harvard Medical School will present two local symposia on eye diseases and the latest research in the field. The events are free to the public, though reservations are required. Topics include the developing science of retinal transplantation to treat AMD, and advances in treatment of other eye diseases such as glaucoma, diabetic retinopathy, and corneal disease.

The symposia take place from 9 a.m. to noon on Saturday, March 22, at the Naples Philharmonic, and Monday, March 24, at the Harborside Convention Center in Fort Myers. Call the institute toll free for reservations at (877) 724-3736, or visit their Web site at www.eri.harvard.edu.