Vision loss is a huge healthcare problem for America’s aging population, with approximately one person in three being diagnosed with some sort of vision-reducing eye disease by age 65. Roger Meyer, M.D., of the New Vision Eye Center, specializes in diseases and surgery of the retina, with a special interest in Age-Related Macular Degeneration (AMD), glaucoma, and diabetic eye care. We talked to Dr. Meyer about his experience treating AMD.
There are two forms of AMD – Dry and Wet. Wet AMD (10 percent of cases, and the more serious of the two types) occurs when blood vessels grow in the back of the eye, and leak blood and fluid into the retina. Haziness and blurriness occur, and the scarring resulting from the leaks leads to permanent loss of central vision. “Injections are the treatment of choice for Wet AMD, as they halt the growth of blood vessels,” says Dr. Meyer. “In about 90 percent of the cases, the injections stop the condition from getting worse, and in about half the cases the vision actually improves.”
The injections are not a one-time thing; they are as frequent as monthly. Dr. Meyer may do an injection every month until the retina is dry, and then cut back by 2-week intervals to every 3 months, as long as leakage doesn’t recur.
In addition to injections, Wet AMD can be treated by a telescopic lens implanted in one eye. It looks like a tiny plastic tube and has lenses that magnify the field of vision. A laser treatment can also be used. Wet AMD is detected by non-invasive tests:
• Fluorescein angiogram. A colored dye is injected in the arm; it travels to the eye and shows abnormalities in blood vessels or the retina.
• Optical Coherence Tomography. An imaging test which identifies retinal thinning, thickening, and swelling. It’s used for an diagnosis and to monitor response to treatment.
Dry AMD is far more common than Wet AMD – 90 percent of cases are of this type. It is caused by the deterioration of the macula, the central portion of the retina. The specific function of the macula is to allow for “central” (as opposed to “peripheral”) vision – which is needed for reading, driving, recognizing faces and other daily activities.
Dry AMD develops gradually and there may be no symptoms, especially if it’s only in one eye, since the non-affected eye can often compensate. Vision changes, when they appear, can include the following, according to the Mayo Clinic:
• Need for brighter light for reading or close work
• Increasing difficulty adapting to low light levels (e.g. entering a dim restaurant)
• Increasing blurriness of printed words
• Gradual increase in the haziness of central or overall vision
• Difficulty recognizing faces
• Blurred or blind spot in center of field of vision
Dry AMD can be detected through an eye exam, in which drusen – yellowish spots of fatty deposits that form in the retina – is looked for. There is also a test called the Amsler Grid, which identifies central vision defects. Dry AMD can’t be reversed, but it progresses slowly and loss of vision is by no means inevitable. Annual eye exams are recommended.
Age is the most definite risk factor for AMD. Others are a family history of AMD, smoking, and being female, light-skinned or of light eye color. Other potential risk factors may contribute to AMD –cardiovascular disease, elevated cholesterol levels and obesity.
AMD currently affects 1.75 million U.S. residents, with that number expecting to grow to 3 million by 2020.
