As we get older, many of our body’s processes start slowing down. For instance, a cut on the hand will take longer to heal after middle age than in youth. That said, it still heals.

Unfortunately, this isn’t the case for the cells at the back of the eye, which simply don’t repair much after we pass age 65. This can lead to age-related macular degeneration (AMD), the primary cause of vision loss in older adults. Over 2 million cases were reported in the U.S. in 2010, and the National Eye Institute estimates AMD will affect more than 3.5 million adults in the country by 2030.

Researchers at UC Santa Barbara have overcome a major hurdle in creating a platform to test therapies for this disease, the most common form of which currently has no treatment. The results appear in the journal PLOS ONE.

Our sharpest vision occurs at the center of the retina, in an area called the macula. “This region is packed full of cones, the cells that are necessary for seeing in detail,” said author Pete Coffey, a researcher at UCSB’s Neuroscience Research Institute. “They are the cells that are involved in reading, recognizing faces, the ability to drive, et cetera.”

Just behind them is a layer of retinal pigment epithelial (RPE) cells. These are responsible for maintaining the health of our rods and cones, the eye’s photo receptors. And these are the cells that stop working properly in AMD.

Age-related macular degeneration comes in two forms. Wet AMD occurs when blood vessels infiltrate the retina. There are treatments for this variety, which aim to prevent the growth of blood vessels where they’re not wanted.