Early Testing Important in Slowing Age-related Macular Degeneration
Jan 01, 2017 02:24PM
● By Jill Cueni Cohen
Age-related macular degeneration, known as AMD, is a common eye disease that causes a distortion in the central vision of older adults. According to Sharon Taylor, MD, of North Park Ophthalmology, people with macular degeneration may see straight lines as warped or bent.
“This is often noticed when reading, as the letters become distorted or some letters may seem to be missing in words,” she explained, adding that patients may not notice it until they inadvertently cover one eye because the other eye has been compensating. “Mild cases of macular degeneration often have no symptoms and are only known to the patient because they are having regular dilated eye exams and have been told by their eye doctor that they have it.”
Genetic predisposition, lifestyle, and environmental factors all contribute to a person’s risk of developing AMD, which is a progressive disease. The most advanced form of AMD is referred to as “wet,” which means that abnormal blood vessels are leaking fluid or blood into the macula; the part of the retina that controls central vision. “Dry” AMD accounts for approximately 80 percent of all diagnoses, but Taylor said that wet AMD is responsible for 90 percent of macular degeneration-related severe central vision loss. “Dry macular degeneration can become wet at any time,” she noted.
Patients who are at higher risk for developing wet AMD can be identified based on examination findings and should be followed closely. “This is critical, because we have a much better chance of being able to preserve vision with early initiation of treatment,” said Taylor, adding that cigarette smoking is a major risk—and the only one a person can avoid.
“Some patients who are at high risk for wet macular degeneration may benefit from having a machine in their home to test their vision on a regular basis to detect early changes,” she added. “We also ask patients to monitor their vision by viewing a grid with each eye individually, called an Amlser grid.”
Optometrist Justin Nock of Dittman Eye Care (with offices in Cranberry and Butler) frequently sees patients with AMD. He recommends genetic testing to determine a patient’s risk of progressing to advanced AMD.
“Macula Risk PGx combines a patient's current AMD status, genetic and non-genetic risk factors to determine their two, five, and 10-year risk of developing advanced AMD,” Nock explained.
The test is administered by a cheek swab and also helps in the selection of eye supplement vitamin formulations. “There's no cure for AMD and you can't resolve it, but certain nutritional supplements have slowed the progression of the disease,” said Nock, recommending a diet rich in leafy green vegetables. He also suggests wearing sunglasses that protect eyes from harmful UV rays in addition to not smoking.
Optometrists, ophthalmologists and retinal specialists across the country feel strongly about whether or not genetic testing should be used as a diagnostic tool, acknowledged Nock, adding, “It’s best for each patient to ask their trusted doctor his or her opinion on this controversial topic.”
Taylor does not recommend genetic testing to her AMD patients unless they are part of a clinical study. “Scientists don't know enough about the complex genetics of AMD to use any existing test, including macula-risk, to effectively screen patients or guide therapy,” she explained.
Treatments for wet AMD were only recently developed. “Now, the first line treatment is with drugs that are called anti-VEGF (anti-Vascular Endothelial Growth Factor) injected into the back of the eye,” said Taylor. “We are able to slow the loss of vision, keep the wet macular changes at bay, and in some cases—approximately 44 percent—actually improve the vision somewhat from the pretreatment level.” Taylor recommends wet AMD sufferers receive this treatment from a retinal specialist.