How the Greenland shark's 400-year lifespan could help scientists protect human eyesight

For years, scientists thought Greenland sharks were basically blind. These deep-sea creatures live in the freezing dark waters of the Arctic and often have parasites clinging to their eyes, so it seemed obvious that their vision was pretty much gone. But a new study from researchers at the University of California, Irvine, says that assumption was wrong. It turns out these sharks, which can live for hundreds of years, may actually see just fine well into old age. The discovery is giving scientists fresh ideas about how human eyes age too, and whether something learned from a giant shark eyeball could eventually help with age-related vision problems in people.The shark that keeps moving its eye toward the lightDorota Skowronska-Krawczyk, an associate professor at UC Irvine, first got curious about this after watching video footage of a Greenland shark drifting through dark Arctic water.