Could being exposed to excess UV in the arctic lead to a human eye color change? If so, what is the mechanism?

The CBS News article Expedition Antarctica: A father and son's journey to save the planet says (in part):

Thirty-two years ago, Robert Swan made history as the first person to walk to both poles. Even as a young man, these grueling expeditions took a harsh toll on his body. Passing directly beneath the hole in the ozone layer, Swan's face became badly burned and his eyes even changed color. But the Arctic explorer now says that all of that physical duress pales in comparison to the agony of watching his son go through the same experience 32 years later. (emphasis added)

Skin color change can happen after exposure to UV light. From Wikipedia:

Melanin is a natural pigment produced by cells called melanocytes in a process called melanogenesis.

Question: Can the human eye really change color due to excess UV light from the Sun, in this case through a polar "hole" in the ozone layer? If so, what is the mechanism?

above: "This winter, Barney and Robert Swan became the first explorers to ever trek to the South Pole surviving exclusively off of renewable energy." Robert (the elder) is on the right. From here. Credit: SHELL-Technical Partners