400-year-old Greenland sharks may hold clues to eye health

Researchers report intact, healthy retinas in Greenland sharks more than 100 years old, and their visual pigment is tuned to blue light suited for deep water.

New research reports that Greenland sharks maintain preserved visual systems well into advanced age. These sharks live deep in near-total darkness, often have parasites on their eyes, and can reach lifespans measured in centuries. The international team analyzed eyes collected under government permits between 2020 and 2024 and used radiocarbon dating of eye tissue to estimate ages. Results were published in Nature Communications. Key findings: - Every examined individual was over 100 years old, with the oldest in the sample estimated at more than 130 years. - Detailed analysis found structurally and molecularly intact retinas with no signs of age-related damage. - The sharks' retinas rely entirely on rod cells; their rhodopsin is tuned near 458 nanometers, a blue wavelength that penetrates deep water. - Corneas transmitted most incoming light despite the presence of parasites on some eyes. - Samples were collected from 2020–2024 under government permits and aged using radiocarbon dating; the work appears in Nature Communications. Summary: The study shows Greenland sharks preserve retinal integrity and key molecular markers of low-light vision over unusually long lifespans, adding to interest in their longevity and DNA repair mechanisms. The authors do not claim a direct solution for human vision loss; any relevance to human eye health remains under study. Undetermined at this time.