Cataracts, Pterygiums, Melanoma (cancer) of the eye
Prolonged sunlight exposure has been linked to pterygiums and cataracts. And, because sunlight can be magnified by the reflective ocean surface, it is all the more important to protect your eyes in and around water.
Compare the pterygium, above, to your eyes after a long day of surfing or sun exposure.
According to Peter Marzano, M.D., the most important disease to protect your eyes against is Melanoma. It can and does occur on the retina and is usually asymptomatic. By the time it is usually found, the eye has to be enucleated (removed) and is already a stage IV (basically- you're done). Dr. Marzano also wrote "If the picture of the diseased retina doesn't scare them, a surfer with one eye and no hair from chemo will."