Age- Related Macular Degeneration Age-Related Macular Degeneration (AMD) is the leading cause of blindness in the United States. It is caused by damage to a localized area of the central retina called the macula. A build-up of waste products under the surface of the retina causes destruction of the sensitive tissues that enable images to be sent to the brain. Cells in the macula break down, causing a gradual or sudden loss of sight in the central part of vision but leaving the peripheral vision unaffected. Although people do not lose all their sight, reading, recognition of faces, watching television and driving are very difficult or impossible. Several factors play a role in the development of AMD. Genetic predispositions as well as environmental factors both contribute to the disease. People with fair skin have a higher incidence of the disease. Things that reduce antioxidants in the body also have an effect (i.e. smoking, poor diet, and lack of exercise). Figure 1 shows the appearance of the normal macula. Figure 1. The image on the left is a cross-section through the macula showing the intricate, light-sensing layers. This is called optical coherence tomography or OCT. The photo shows the normal macula as your retina specialist sees it during examination.
What are the different types of macular degeneration? Macular degeneration is classified as either dry or wet. Dry macular degeneration The dry form is more common than the wet (about 87 percent of patients). In dry AMD, the cells of the macula decay and disintegrate and cause loss of vision without turning into the wet form of the disease. However, it is also possible for early-stage dry AMD to suddenly change into the wet form. Figure 2 shows changes from dry macular degeneration. Figure 2. The photo on the left is a cross-sectional image through the macula (OCT). Bumps under the surface are called drusen and these lesions as well as loss of tissue causes loss of vision slowly over time. The photo on the right is what a retinal specialist will see in a patient with dry macular degeneration. Wet macular degeneration The second form, wet AMD, is more aggressive in its development. It is caused by the growth of abnormal blood vessels in the retina that can leak and lead to scarring and loss of central vision. A sudden loss of vision or sudden distortion of vision is what most patients notice. Figure 3 shows changes from wet macular degeneration.
Figure 3. The photo on the left is a cross-sectional image through the macula (OCT). Dark spaces and swollen areas represent fluid caused by leakage from abnormal blood vessels. The photo on the right shows blood under the retina that can cause severe scarring and loss of vision. Is there a difference between macular degeneration and age-related macular degeneration? Macular degeneration is usually age-related, affecting people over 65 years old, so the terms are often used interchangeably. What are the signs and symptoms of macular degeneration? Early signs include: straight lines appearing wavy, fuzzy vision, and shadowy areas in your central vision. Our doctors may find indicators before you have any symptoms, so regular eye exams with an ophthalmologist are very important for an early diagnosis. What is an Amsler grid used for? Amsler grids are used to detect these vision problems. This grid consists of straight lines, with a reference dot in the center. Someone with macular degeneration may see some of the lines as wavy or blurred, with some dark areas at the center.
Amsler Grid How is macular degeneration diagnosed? A dilated eye exam is performed to view the back of the eye using a procedure called fundoscopy. If wet AMD is suspected optical coherence tomography (and possibly a fluorescein angiogram, Figure 4) will be performed.
Figure 4. The photo on the left shows one of our photographers injecting dye into a vein in a patient s arm and then taking special photographs of the back of the eye (fluorescein angiography - photo on the right). Does macular degeneration usually affect both eyes? Yes, although it may only be diagnosed in one eye, most patients are likely to develop it in their second eye as well. It is very important to monitor your vision and to report any deterioration to your doctor immediately. Can macular degeneration be treated? There is no current treatment to prevent vision loss for advanced dry agerelated macular degeneration. However, a specific high-dose formula of antioxidants and zinc may delay progression to the advanced stage in certain cases. The wet form of the disease can be treated with injections of medication into the eye (and occasionally with laser). Injections into the eye? The first-line treatment for wet AMD is injections of medication (Avastin, Lucentis, or Eylea) into the eye. Before development of these revolutionary medications all patients with wet AMD lost vision despite therapy (such as laser). With these medications patients with wet AMD actual have visual recovery and stabilization of vision if caught early enough. Though anxiety provoking, these injections can be comfortably done in clinic by a retina specialist.
I ve heard that stem cells can cure macular degeneration. Is that true? The quick answer is no, not yet, but recent studies are very promising. Researchers at UCLA have published preliminary reports that injection of special stem cells under the retina in humans is feasible and show promise for visual rehabilitation in patients with macular degeneration. Embryonic stem cell trials for macular degeneration: a preliminary report http://www.thelancet.com/journals/lancet/article/piis0140-6736(12)60028-2/abstract Related Websites American Academy of Ophthalmology Preferred Practice Pattern Guidelines on Age-Related Macular Degeneration http://one.aao.org/ce/practiceguidelines/ppp_content.aspx?cid=f413917a-8623-4746-b441-f817265eafb4 National Eye Institute Facts about Age-Related Macular Degeneration http://www.nei.nih.gov/health/maculardegen/armd_facts.asp Savannah Center for Blind and Low Vision http://www.savannahcblv.org/