Research Brings Hope for Patients with AMD and Low Vision
February is Age-related Macular Degeneration (AMD) and Low Vision Awareness Month. AMD is the leading cause of blindness in the United States and the developed world, as well as of low vision, which means that even with glasses, contact lenses, medicine, or surgery, people find everyday tasks difficult to perform. AMD destroys vision through proliferation of new blood vessels (“wet” or neovascular AMD, reflecting about 10% of cases) or where photoreceptors (light-sensitive cells in the retina) die away (“dry” or atrophic AMD, accounting for 90% of cases). Since AMD affects the central part of the retina—called the macula—the resulting vision loss makes it increasingly difficult for an individual to read and drive, thereby affecting productivity, independence, and quality of life and adding significantly to the annual cost burden of eye disease, currently $145 billion but expected to grow to $717 billion dollars by 2050 when adjusted for inflation.
Since Americans fear vision loss more than most other health conditions, as reported in a 2014 Research!America survey conducted for AEVR, federally funded research at the National Institutes of Health (NIH) and its National Eye Institute (NEI) has focused on the causes of and treatments for AMD. Numerous risk factors are associated with AMD. Non-modifiable factors include aging, genetics, gender, and race, while modifiable factors include obesity, smoking, high blood pressure, high cholesterol, cardiovascular disease and light exposure. NEI-funded research has identified more than 50 common and rare gene variants associated with AMD, and genetics may account for 60% of the cause of the disease.
Since 2006, there have been dramatic improvements in wet AMD treatment from “anti-VEGF” therapy, developed in part from NIH funding. These Food and Drug Administration (FDA)-approved drugs are injected into the eye, inhibiting the abnormal blood vessel growth due to Vascular Endothelial Growth Factor (VEGF), and stabilizing vision loss—and, in a proportion of cases, improving lost vision. These drugs have also been approved for Diabetic Eye Disease.
Although dry AMD is more prevalent, no current treatments exist to restore vision in this condition. There are several promising therapies on the horizon for dry AMD, including retinal stem cell therapy clinical trials which are now proceeding after many years of preclinical development in animal studies. In the case of stem cell-derived retinal pigment epithelial cell transplantation, photoreceptors could be grown in the laboratory—essentially a “mini-retina in a dish”—and then injected into the eye to “patch” the degenerated retina in dry AMD. The goal for these transplanted cells is to make synapses—or connections—with host inner retinal neurons to regenerate the visual circuit.
Recently, the NEI reported that it has supported more than 170 new AMD-related research grants in fiscal years 2010-2016. It has also established an AMD Pathobiology Working Group within its National Advisory Eye Council which will issue a white paper in 2018 that evaluates current knowledge and identifies what we still need to learn, such as the relationship between genes and biological pathways and how to diagnose and treat the disease much earlier.
Stay tuned, these are exciting times for AMD research!
James F. Jorkasky is executive director of the Alliance for Eye and Vision Research (AEVR).