Researchers at Keck Medicine of USC are launching a phase 2b clinical trial examining if stem cells bioengineered to replace failing cells in the retina damaged by macular degeneration could restore eyesight. Credit: Regenerative Patch Technologies LLC 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