By Staff Reports
(DGIwire) – Once a person has been diagnosed with age-related macular degeneration (AMD), they are likely to have a lot of questions. An eye care professional who has examined the patient’s eyes and is familiar with his or her medical history is the best person to answer specific questions, but here are some very basic facts:
- What is AMD? AMD is a common eye condition and a leading cause of vision loss among people age 50 and older. AMD results in damage to the macula, a small spot near the center of the retina and the part of the eye needed for sharp, central vision, according to the National Eye Institute (NEI), a division of the National Institutes of Health. In some, AMD advances slowly; in others, the disease progresses faster and may lead to vision loss in one or both eyes.
- Who is at risk for AMD? Age is a major risk factor, with the disease most likely to occur after age 60, reports the American Academy of Ophthalmology. Other risk factors include having a family history of AMD, sun exposure, smoking, etc. Researchers have also found links between AMD and some lifestyle choices. Regular exercise, maintaining normal blood pressure and eating a healthy diet are recommended.
- How is AMD detected? Only a comprehensive eye exam can detect AMD. According to the NEI, the exam may include a visual acuity test, a dilated pupil exam and a look at an Amsler grid (which can reveal changes in central vision). The doctor might also suggest a fluorescein angiogram, in which pictures of a dye are taken as it passes through blood vessels in the eye, and optical coherence tomography.
- What are the main types of AMD? The “dry” form of macular degeneration is characterized by the presence of yellow deposits, called drusen, in the macula, noted WebMD. The “wet” form of macular degeneration is characterized by the growth of abnormal blood vessels from underneath the macula. These blood vessels leak blood and fluid into the retina, interfering with vision and eventually forming a scar and leading to permanent loss of central vision. Therapies targeted to reduce the growth of these blood vessels are commonly used to maintain vision for as long as possible.
- What research is being done for AMD? Some research is focused on the proteins that trigger the process in wet AMD that may cause irreversible retinal scarring, often a secondary component of this later-stage disease. The goal is to see if it is possible to regulate or block these proteins in the first place. RXi Pharmaceuticals is showing how this approach could be possible.
“It has been shown that a naturally occurring phenomenon called RNA interference—‘RNAi’ for short—can target and destroy specific RNAs before they can serve as templates for the generation of 100s to 1000s copies of the coded protein,” says Dr. Geert Cauwenbergh, President and CEO of RXi Pharmaceuticals. “The theory is, ‘reduced scar proteins, reduced retinal scarring.’ We have developed a therapeutic platform of self-delivering RNAi compounds, called sd-rxRNA®. The first of these compounds, RXI-109, is in development to target connective tissue growth factor (CTGF), a key regulator of scar formation in the eye and skin.”
The company is conducting an ongoing Phase 1/2 clinical trial in patients with wet AMD to evaluate the safety and clinical activity of RXI-109 to prevent the progression of retinal scarring.
As more is learned about the mechanisms behind wet AMD, new therapies may become available to help those grappling with the vision loss it can bring.