Macular Degeneration (cont.)
Andrew A. Dahl, MD, FACS
Andrew A. Dahl, MD, FACS
Andrew A. Dahl, MD, is a board-certified ophthalmologist. Dr. Dahl's educational background includes a BA with Honors and Distinction from Wesleyan University, Middletown, CT, and an MD from Cornell University, where he was selected for Alpha Omega Alpha, the national medical honor society. He had an internal medical internship at the New York Hospital/Cornell Medical Center.
William C. Shiel Jr., MD, FACP, FACR
William C. Shiel Jr., MD, FACP, FACR
Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.
In this Article
What are signs of macular degeneration?
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In both dry and wet forms of macular degeneration, the ophthalmologist may find decreased visual clarity (acuity) with preservation of peripheral vision and changes in the central retina visible with the ophthalmoscope.
How is macular degeneration diagnosed?
Your ophthalmologist may suspect the diagnosis of AMD if you are over age 60 and have had recent changes in your central vision. To look for signs of the disease, he or she will use eyedrops to dilate, or enlarge, your pupils. Dilating the pupils allows your ophthalmologist to view the back of the eye better.
Early AMD is often diagnosed during a comprehensive eye exam in patients without significant symptoms. This eye exam includes having drops placed in your eyes to enlarge, or dilate, the pupils. Your ophthalmologist will carefully examine the central portion of the retina to determine the presence or absence of AMD using various illuminating and magnifying devices.
During the eye exam, you may be asked to look at a checkerboard pattern called an Amsler grid. When looking at an Amsler grid with one eye, patients with AMD may notice that the straight lines of the checkerboard appear wavy or are missing.
Other diagnostic tests that your ophthalmologist may perform include retinal photography, fluorescein angiography and optical coherence tomography. All of these can help to differentiate between dry and wet forms of AMD and also document the abnormalities so that progression and response to treatment can be better measured.
What is the treatment for wet macular degeneration?
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Wet AMD can be treated with laser surgery, photodynamic therapy, and injections into the eye. None of these treatments is a permanent cure for wet AMD. The disease and loss of vision may progress despite treatment.
Laser surgery is used to destroy the fragile, leaky blood vessels. A high energy beam of light is aimed directly onto the new blood vessels to eradicate them, preventing further loss of vision. However, laser treatment may also destroy some surrounding healthy tissue and some vision. Because of this, only eyes with new vessels away from the exact center of the vision can be treated. This represents only a small proportion of patients with AMD. Laser surgery is only effective in halting or slowing visual loss if the leaky blood vessels have developed away from the fovea, the central part of the macula. Even in treated cases, the risk of new blood vessels recurring after treatment is significant and further or other treatment may be necessary.
Photodynamic therapy uses a drug called verteporfin (Visudyne) being injected into a vein of the arm. A light is then directed into the eye to activate the drug adhering to the blood vessels in the eye. The activated drug destroys the new blood vessels and leads to a slower rate of vision decline. Photodynamic therapy may slow the rate of vision loss. It does not stop vision loss or restore vision in eyes already damaged by advanced AMD. Treatment results often are temporary. Retreatment may be necessary.
Within the last seven years, injections into the eye with drugs specifically developed to stop the growth of new blood vessels have revolutionized the treatment of wet macular degeneration. We have learned that a specific chemical called vascular endothelial growth factor (VEGF) is necessary for the new blood vessels to grow under the retina. Drugs that counter VEGF (anti-VEGF pharmacotherapy) can be injected into the eye to arrest development of new blood vessels and sometimes cause them to regress. These drugs are injected in the ophthalmologist's office and may need to be given as frequently as monthly. Careful observation of the eye on a monthly basis to determine the drug effect is necessary. With this treatment, visual loss can often be halted or slowed and some patients will even experience some improvement of vision. Newer drugs currently under review may need to be given less frequently. Photodynamic therapy and laser ablation have been largely, if not completely, abandoned in faver of VEGF inhibitors. New and more effective anti-VEGF medicines are on and approaching the market. If diagnosed and treated early, the patient's chances of a better outcome are improved.
In patients with far advanced macular degeneration on both eyes, surgery to implant a telescopic lens in one eye is an option. The telescope implant, which surgically replaces the eye's natural lens, magnifies images while reducing the field of vision (peripheral vision). The telescopic lens implant may improve both distance and close-up central vision.
Medically Reviewed by a Doctor on 1/23/2014
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