How Better Models of Macular Degeneration Could Help Prevent Vision Loss

As some people age, the specialized receptors in their eyes that detect light can begin to break down, a condition called age-related macular degeneration (AMD). When this happens, cellular debris can build up around the retina, the region of the eye affected by AMD. As this debris builds up, the cells get less healthy—like trash on top of a garden bed choking out the plants underneath.

But scientists still don’t fully understand exactly what causes all of this debris, or how it damages the retina on a molecular level. They’re also not sure whether cellular debris appears before or after the retina starts to deteriorate. That’s because all of the experimental models they have to study AMD currently fall short.

BrightFocus Macular Degeneration Research grant recipient Brittany Carr, PhD is working to fix that, a mission that will help scientists better understand the warning signs of AMD progression, and could even lead to new ways to treat and prevent this leading cause of blindness.

She brings more than a decade of experience in vision science to the table. Dr. Carr has investigated everything from congenital eye conditions to the mechanisms of myopia. Her research has already uncovered novel therapeutic targets for vision loss diseases, with many new potential discoveries for AMD on the horizon.

The Gaps in AMD Research

With support from Macular Degeneration Research, Dr. Carr is developing new experimental models that will help researchers better understand AMD. Her work focuses on the role that cellular debris build-up in the retina plays, a feature of AMD that most current models overlook.

“There is no perfect model system,” said Dr. Carr. “One of the difficulties in understanding AMD is that there is no animal model that fully encapsulates all features of the disease, and it is nearly impossible to replicate tissue-tissue interactions in a cell culture environment.”

So Dr. Carr is developing her own experimental models. Her work will help researchers test new treatments, including gene-based therapies and drugs, which could eventually lead to breakthroughs in how we treat or even prevent AMD.

New Technologies

Dr. Carr’s new model focuses on frogs, which also develop debris in their retinas as they age. Her method uses CRISPR gene-editing technology, a technique that allows scientists to make precise modifications to DNA. By probing a gene that is also important in human vision loss, Dr. Carr can investigate the origin point for cellular debris related to AMD.

She said that as technology advances, now is a particularly promising time in vision research.

“With the advent of CRISPR and AI technologies, biomedical research is evolving and breakthroughs are accelerating at unprecedented rates,” Dr. Carr said. “I believe that the future of AMD research is going to be extremely productive and exciting.”

“[I’m] excited to continue to work together with BrightFocus to do exceptional science and unlock the secrets of AMD so that one day, it is no longer a devastating disease.”

Working with lab models that naturally develop key features of AMD allows scientists to better understand how the disease starts and worsens over time. These new techniques will give researchers a strong starting point for learning more about what happens inside the eye during AMD, what early changes begin before symptoms appear, whether there are clues that predict if the disease will get worse, and if there are new ways to target the disease with treatments.

Stopping Vision Loss

So far, Dr. Carr’s work has already shed light on the formation of one type of cellular debris, called subretinal drusenoid deposits. Her next steps will investigate the timeline of how this debris forms, and the role that inflammation plays. Answering these questions is essential to develop treatments that could stop vision loss.

“Once we identify the origin and composition of these deposits, we can then start teasing apart ways to treat and maybe even prevent them,” Dr. Carr explained.

She said that as an early-career scientist, support from Macular Degeneration Research has been pivotal to her work.

“[I’m] excited to continue to work together with BrightFocus to do exceptional science and unlock the secrets of AMD so that one day, it is no longer a devastating disease,” she said. “Your donations have made a significant and tangible difference to the present, and future, of discovery vision science and AMD research in North America, and the impacts of your generosity will be felt for years to come.”