Unfortunately it also seems like these sharks are plagued by parasites in their eyes:
The shark is often infested by the copepod Ommatokoita elongata, a crustacean that attaches itself to the shark's eyes.[17] The copepod may display bioluminescence, thus attracting prey for the shark in a mutualistic relationship, but this hypothesis has not been verified.[18] These parasites can cause multiple forms of damage to the sharks' eyes, such as ulceration, mineralization, and edema of the cornea, leading to almost complete blindness.[11] This does not seem to reduce the life expectancy or predatory ability of Greenland sharks, due to their strong reliance on smell and hearing.