New NEI Study Investigates Age-Related Macular Degeneration

Episode # 38
Uploaded: February 26, 2010
Running Time: 5:15

SCHMALFELDT: From the National Institutes of Health in Bethesda, Maryland, this is CLINICAL CENTER RADIO. Keeping our eyes healthy is important throughout our lives, yet millions of Americans lose some of their vision every year to a variety of causes. One of those causes is known as age-related macular degeneration or AMD, a disease associated with aging that gradually destroys sharp, central vision necessary for seeing objects clearly. Dr. Catherine Meyerle is the principal investigator of a National Eye Institute protocol studying the treatments for this disorder.

MEYERLE: (0:00-0:35) Age-related macular degeneration is one of the leading causes of blindness in the United States. There are two different forms, the wet form which is also known as the neovascular form, and the dry form. There are different stages of the dry form; there is early, intermediate or advanced.

SCHMALFELDT: The presence of yellowish deposits under the retina called "drusen" are the first signs of early AMD. People with intermediate AMD have a significant presence of drusen . Advanced AMD involves a breakdown of light sensitive cells and supporting tissue in the central retinal area. This breakdown can cause a blurred spot in the center of your vision which may get bigger and darker over time or it can make straight lines appear wavy. Advanced AMD presents itself in two forms: wet and dry. This study specifically addresses wet age-related macular degeneration.

MEYERLE: Wet macular degeneration, unlike the advanced dry, instead of a thinning of tissue you get abnormal blood vessels that grow underneath your retina. These abnormal blood vessels tend to bleed and leak fluid and this fluid and blood goes into your macula itself. And the problem with fluid and blood in your macula is it distorts the cells that enable you to see, the photoreceptors, so they don't function as well and this can ultimately if not treated, lead to scarring, and once there is scarring we can't reverse scarring. And if you have a scar on your macula you will have a central area where you can't see, we call it a scotoma. If I have a scar on my macula, I might look at someone's face and not be able to see their nose and part of their eyes, maybe I'll just be able to see their chin.

SCHMALFELDT: More than 1.7 million Americans have the advanced form of AMD with about 200,000 new cases of wet macular degeneration diagnosed each year. This study is seeking participants 50 years of age and older with a diagnosis of wet age-related macular degeneration to study those leaky blood vessels Dr. Meyerle described. This protocol provides participants with the standard treatment for this disorder, a drug called Lucentis, although it does involve a little something extra.

MEYERLE: This study is looking at high speed indocyanine green angiography. We call it ICG for short. ICG is an imaging test where we inject green dye in your arm and it circulates in your body and it helps us visualize the vessels underneath the retina called the choroid, and this is where you can develop the abnormal vessels associated with wet macular degeneration… This study is different because we are looking at the actual abnormal vessels themselves as opposed to looking just at the fluid and the leakage.

SCHMALFELDT: Essentially, this study combines standard treatment of wet AMD combined with the ICG to see if there is any effect of the medication on the abnormal blood vessels themselves or if it only affects the fluid. This is important information because currently people may respond differently to Lucentis.

MEYERLE: With Lucentis therapy, some patients need injections monthly for years, and other patients, after they have a few induction injections, they can go a long time without an injection. And why is there this variability in response to therapy? There might be something different about these characteristics of these abnormal blood vessels and that's what this study is designed to look at.

SCHMALFELDT: If you would like more information about this study or one of the 1,500 other studies offered at the NIH Clinical Center, log on to http://clinicalcenter.nih.gov, or e-mail prpl@mail.cc.nih.gov. You may also call our call center toll free at 1-800-411-1222. From America's Clinical Research Hospital, this has been CLINICAL CENTER RADIO. In Bethesda, Maryland, I'm Bill Schmalfeldt at the National Institutes of Health, an agency of the United States Department of Health and Human Services.

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