Research led by University of California Associate Professor Dorota Skowronska-Krawczyk suggests that the world’s longest-living vertebrate, the Greenland shark, may hold valuable clues for preserving vision as humans age.
The findings, published in Nature Communications, indicate that Greenland sharks – some of which are estimated to live for up to 400 years – maintain functional vision throughout their lifespan, showing no signs of retinal degeneration despite extreme age and harsh environmental conditions.
The work challenges long-held assumptions that Greenland sharks are functionally blind. The species inhabits deep, dim Arctic waters and is commonly affected by parasites that attach to the eye, leading scientists to believe vision was largely redundant.
However, A/Prof Skowronska-Krawczyk observed that sharks actively track light with eye movements, suggesting visual function is preserved.
According to the research, a robust DNA repair mechanism appears to protect retinal cells over centuries, while the sharks’ visual systems are finely adapted to low-light environments. The team found that rhodopsin, a protein critical for dim-light vision, remains active in the shark retina and is tuned to detect blue light.
The study builds on earlier work published in Science in 2016 by marine biologist Professor John Fleng Steffensen.
Eyeballs from Greenland sharks caught between 2020 and 2024 near the University of Copenhagen’s Arctic Station in Greenland were examined after being preserved by researchers. Histological analysis conducted at UC Irvine found no evidence of cell death in retinal tissue.
Ms Emily Tom, a UC Irvine PhD student and physician-scientist in training, carried out detailed vision-specific analyses and said the results demonstrate the value of studying long-lived species to better understand aging and ocular health.
A/Prof Skowronska-Krawczyk said the findings could open new avenues for preventing age-related vision loss and treating diseases such as macular degeneration and glaucoma.
She added that while future research funding remains uncertain, the work underscores the importance of basic science in uncovering mechanisms that keep tissues healthy over a lifetime.
