Age-related macular degeneration is the most common cause of vision loss and blindness among Americans age 65 and older. The disease worsens over time and primarily damages central vision, making it difficult to see faces, read text or focus on objects directly ahead. As the condition progresses, people may experience blurry areas, dark patches or blind spots in the center of their vision.

Researchers are now launching a new clinical trial that could offer hope to people with advanced dry age-related macular degeneration. This form of the disease is the most widespread and currently has very limited treatment options.

Scientists at the USC Roski Eye Institute, part of Keck Medicine of USC, are beginning a phase 2b clinical trial to test whether stem cells can be used to replace damaged retinal cells and potentially restore vision. The stem cells are attached to an ultra-thin implant, thinner than a strand of hair, designed to hold the cells in place once inserted into the eye.

"We are hoping to determine if the stem-cell based retinal implant can not only stop the progression of dry age-related macular degeneration, but actually improve patients' vision," said Sun Young Lee, MD, PhD, a retinal surgeon with Keck Medicine and principal investigator of the Keck Medicine study site. "The findings could be groundbreaking because while there are a few treatments available that delay the progress of macular degeneration, there are none able to reverse the damage already done."

Encouraging Results From Earlier Research

The new trial builds on earlier research conducted by USC Roski Eye Institute specialists involving a small group of patients. That initial study found the implant was safe, remained securely positioned in the eye and was successfully absorbed into the retinal tissue. Notably, 27% of participants experienced some level of vision improvement.

"The earlier phase of the clinical trial showed the treatment to be safe with the potential to benefit patients' vision; this next phase will investigate whether the therapy can achieve clinically significant improvements in vision," said Lee, who is also an associate professor of ophthalmology and physiology & neuroscience at the Keck School of Medicine of USC.

How the Retinal Implant Is Designed to Work

Roughly 20 million Americans are living with age-related macular degeneration. This figure includes people with wet macular degeneration, which is less common but typically more severe.

The disease affects the macula, a small area at the center of the retina that is essential for sharp, detailed vision. In advanced stages, cells known as retinal pigment epithelium (RPE) cells become damaged or stop functioning. These cells play a critical role in maintaining healthy vision, and their loss leads directly to visual decline.

The implant being tested in the trial is created from embryonic stem cells that are grown in a laboratory and developed into RPE cells. During an outpatient surgical procedure, Keck Medicine eye surgeons will place a thin layer of these lab-grown cells directly into the retina.