Ancient Sharks Keep Perfect Vision for 400 Years Through DNA Repair

The Discovery That Changes Everything About Aging Eyes

When UC Irvine researcher Dorota Skowronska-Krawczyk watched video footage of a Greenland shark slowly drifting through Arctic waters, she noticed something extraordinary. "You see it move its eye," she observed, "The shark is tracking the light—it's fascinating." This simple observation would challenge everything scientists thought they knew about aging and vision.

For decades, researchers believed these ancient predators were essentially blind. Living in the dim depths of the ocean and often infested with parasites that attach to their eyes, scientists believed the large, long-lived species to be functionally blind. The sharks' opaque eyes and frequent parasite companions seemed to confirm this assumption. But Skowronska-Krawczyk's curiosity led to a groundbreaking discovery that could revolutionize how we understand vision and aging.

Baseball-Sized Eyes Reveal Centuries-Old Secrets

"I opened the package, and there was a giant, 200-year-old eyeball sitting on dry ice just staring back at me," recalls Emily Tom, a UC Irvine PhD student who helped analyze the specimens. Working with mouse eyeballs the size of papaya seeds, the team had to figure out how to scale up to baseball-sized eyeballs.

The research team, collaborating with scientists from multiple institutions, collected Greenland sharks between 2020 and 2024 near Disko Island, Greenland. What they found defied all expectations. The sharks' retinal tissue showed no signs of degeneration, even in individuals estimated to be around 200 years old. Even more remarkable, rhodopsin, a protein critical for low-light vision, remained active and tuned to detect blue light, which dominates their Arctic environment.

DNA Repair Mechanism Holds Key to Lifelong Vision

Published in Nature Communications, the findings suggest that a DNA repair mechanism enables these sharks—some of which live for 400 years—to maintain their vision over centuries with no signs of retinal degeneration. This discovery represents a fundamental shift in understanding how biological systems can resist age-related decline.

The most eye-opening discovery was the "robust expression" of genes linked to DNA repair in the retina, "which may help support long-term maintenance of retinal integrity over the Greenland shark's extreme lifespan." Unlike humans, who typically experience vision deterioration with age, these sharks have evolved sophisticated cellular machinery to continuously repair damage to their visual system.

Revolutionary Implications for Human Vision

The implications extend far beyond marine biology. For Skowronska-Krawczyk, the findings open the door to discovering new approaches to avoiding age-related vision loss and eradicating eye diseases such as macular degeneration and glaucoma. Understanding how Greenland sharks maintain healthy retinal cells for centuries could inform entirely new therapeutic strategies.

Discovering how a Greenland shark maintains its healthy ocular cells and tissues for centuries may help develop therapies for diseases including glaucoma and macular degeneration that often develop later in life. The research suggests that rather than accepting vision loss as inevitable, we might learn to enhance our own DNA repair mechanisms to preserve sight throughout our lifespans.

This breakthrough represents more than just an interesting biological curiosity—it offers genuine hope for millions facing age-related vision decline. By studying nature's most successful examples of longevity, scientists are uncovering the molecular secrets that could help humans maintain their most precious sense for a lifetime.