AMD is the number-one cause of vision loss in the U.S. The macula is a part of the retina in the back of the eye that ensures that our central vision is clear and sharp.
Age-related macular degeneration (AMD) occurs when the arteries that nourish the retina harden. Deprived of nutrients, the retinal tissues begin to weaken and die, causing vision loss. Patients may experience anything from a blurry, gray or distorted area to a blind spot in the center of vision. Recent developments include genetic testing to determine your risk of developing severe AMD. Severe AMD can be treated with medications injected into the eye.
Avastin: Avastin is an antibody to vascular endothelial growth factor (VEGF), a protein responsible for angiogenesis (new blood vessel growth). Because of Avastin's ability to bind to VEGF, the VEGF molecule is then unable to bind to its receptor and hence angiogenesis does not occur. Avastin is approved as an anti-tumor medication for use in specific cancer types. Although Avastin is not approved by the FDA for ocular use, it has proved to be highly efficacious for use in cases of retinal or choroidal neovascularization and macular edema. It has been in routine use for eye disease "off label" since 2005.
Lucentis: Lucentis is a modified version of Avastin. Like Avastin, Lucentis binds VEGF which stops VEGF from binding to its receptor and promoting angiogenesis. Lucentis is a smaller and may better penetrate into the retina. Lucentis has specifically been designed for use in the eye to treat neovascular (wet) macular degeneration, among other retinal disease, and is approved for this use by the FDA. The CATT trial has shown that Lucentis and Avastin work to about the same degree for patients with wet macular degeneration.
Visudyne drug treatment (Photodynamic Therapy or PDT).
Visudyne was the first drug therapy approved for treatment of the wet form of macular degeneration. It is only for those patients who have new blood vessel growth (neovascularization) under the retina in a well defined, distinctive pattern known as "predominantly classic." About 40 to 60 percent of new wet AMD patients have this form of the disease, according to Novartis, the company that markets Visudyne.
In this treatment procedure, the doctor injects Visudyne into your arm, then activates the drug as it passes through the retinal blood vessels by shining a low-energy laser beam into your eye. Visudyne is activated by the laser light, which produces a chemical reaction that destroys abnormal blood vessels. The procedure is virtually painless, according to Novartis.
One in six Visudyne patients shows improved vision, or about twice as many patients as those who do not undergo Visudyne therapy. Recent studies also indicate significant slowing of AMD progression in many patients receiving Visudyne drug treatment.
In one study, 225 eyes with wet AMD were treated with Visudyne, and 114 comparable eyes were not. After 24 months, legal blindness occurred in 28 percent of the Visudyne group and in 45 percent of the non-treated group.
Visudyne sometimes is used in addition to Lucentis or Avastin as a treatment for wet macular degeneration. Other light-activated drugs designed to perform in ways similar to Visudyne are currently in development.
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