New discoveries in molecular and cellular biology are expanding our understanding of AMD and accelerating the pace of research. Scientists and practitioners are conducting investigations to learn more about the underlying causes of AMD and testing a number of promising therapies for both the dry and wet forms. Visit the National Institutes of Health's Web site ClinicalTrials.gov for details about specific studies for macular degeneration.
Cell Cycle Modifiers
These drugs, which may be taken orally, minimizes the build-up of waste deposits in the retinal cells. Accumulations of these deposits interfere with the retina's ability to nourish photoreceptors - the eye's light-sensing cells - a characteristic of dry AMD. A Phase II study of one these drugs, Fenretinide, did not demonstrate a definite beneficial effect on the course of advanced dry AMD. It was suggested that the medication may help prevent progression to wet AMD. However, further testing is needed in a larger study population to confirm these initial findings.
Anti-Angiogenic Drugs and Combination Therapies
A number of other pharmacological agents are being studied to improve or refine current treatments of wet AMD. Many of these therapies, such as anti-VEGF and anti-inflammatory drugs, are being tested in combination with Lucentis or Avastin to learn if treatment benefits can be prolonged. For example, researchers at Casey Eye Institute are testing the safety and effectiveness of a combination therapy of Lucentis and pazopanib, a topical eye drop that targets anti-VEGF receptors.
Researchers are beginning to test the safety and effectiveness of gene therapy as a potential new treatment for wet AMD.Casey Eye Institute recently joined an early stage clinical trial in which a single injection of two genes is delivered directly to the retina, where they express helpful anti-angiogenic proteins. The aim is to preserve vision by blocking the growth of harmful new blood vessels in a sustained fashion.The treatment, called RetinoStat®, was found to be safe in an earlier group of study patients.Casey is testing a final group in the clinical trial, which is sponsored by Oxford Biomedica.
Scientists are studying the use of human stem cells to aid in the survival and improvement in the function of retinal cells affected by degenerative retinal diseases, and ultimately replacing them in the retina. The hope is to preserve vision and ultimately restore vision loss in these patients. Investigations are underway that will help determine how safe and effective they may be in the human eye.
A promising class of biomedicines contains neuroprotective proteins that slow or prevent the degeneration of photoreceptor cells in the retina. These experimental therapies are being tested in patients with retinitis pigmentosa (RP) and dry AMD.
Intraocular surgery has been used to remove blood and new blood vessels from behind the retina in patients with AMD. While often technically successful, the procedure did not improve vision.
Surgical approaches also include techniques in which the retina is moved or relocated slightly to an area where the underlying tissues are healthier. A laser is used to destroy the new blood vessels in the hope of preventing them from growing back to their original location beneath the center of the macula. Complications are relatively common and this treatment is not routinely performed.
Retinal Cell Transplantation
Studies have been carried out in the area of retinal and retinal pigment epithelial cell transplantation. Certain transplanted cells have been shown to survive in the macula, but restoration of function with improved vision has been disappointing.
Because AMD is so widespread and treatment options limited, numerous remedies claim to restore vision. Some of these include microcurrent stimulation, various herbs, rheotherapy and magnet therapy. We do not recommend these and other treatments that have not undergone rigorous scientific testing.