What Greenland Sharks Are Teaching Us About Aging Eyes - Science Friday Recap

Podcast: Science Friday

Published: 2026-01-15

Duration: 18 minutes

Guests: Dr. Dorota Skowronska-Krawczyk, Dr. Macarena Garcia Marin

Summary

Greenland sharks have remarkably healthy eyes despite living for hundreds of years, potentially offering insights into preventing human eye degeneration. Their eye health is attributed to efficient DNA repair mechanisms.

What Happened

Greenland sharks live extraordinarily long lives, often surpassing 400 years, yet their eyes remain in good health, challenging previous assumptions that they were nearly blind. Dr. Dorota Skowronska-Krawczyk, a molecular biologist, explains that these sharks have highly efficient DNA repair mechanisms that maintain their eye health, suggesting potential clues for combating human eye degeneration.

The sharks' eyes, despite appearing glazed over, do not develop cataracts or other common signs of aging found in human eyes. This discovery was surprising, given that human eyes typically begin showing signs of deterioration by age 60 or 70. The cold environment in which the sharks live may slow their metabolism, contributing to their longevity and eye health.

Dr. Skowronska-Krawczyk's research emphasizes the importance of the sharks' DNA repair mechanisms, which are more active and efficient compared to those in humans. She suggests that these findings could lead to new treatments for human eye conditions by enhancing similar DNA repair pathways in humans.

The episode also touches upon the technical marvel of the James Webb Space Telescope (JWST), whose mirrors are polished to an extraordinary degree of flatness, surpassing previous analogies comparing its imperfections to the size of a baseball. Dr. Macarena Garcia Marin explains that this precision is crucial for observing distant galaxies and nearby objects with exquisite detail.

The development of the JWST required groundbreaking technologies, particularly in mirror polishing and measuring imperfections. These advancements have trickled down into medical applications, such as eye surgery, where similar techniques are used to diagnose and measure eye surfaces.

Listener Leon from Kennewick, Washington, finds inspiration in the intersection of science and spirituality, seeing the study of space as a way to understand the universe's creation and his relationship with God. Dr. Garcia Marin acknowledges this perspective, noting that the awe of studying the universe often leads to contemplating life's big questions.

The episode concludes by highlighting the collaborative effort required to bring the JWST project to fruition, involving thousands of scientists and engineers. The telescope's success is attributed to meticulous planning and teamwork, showcasing human ingenuity in understanding the cosmos.

Key Insights

• Greenland sharks can live over 400 years without developing cataracts or common signs of eye aging, attributed to highly efficient DNA repair mechanisms in their eyes.
• The cold environment of Greenland sharks may slow their metabolism, contributing to their longevity and maintaining eye health, unlike human eyes which typically show deterioration by age 60 or 70.
• Research into Greenland sharks' DNA repair mechanisms offers potential pathways for developing treatments for human eye conditions by enhancing similar pathways in humans.
• The James Webb Space Telescope's mirrors are polished to a degree of flatness that exceeds previous standards, enabling precise observations of distant galaxies and influencing medical technologies like eye surgery.