Here's what we do know about ocular melanoma : It's a type of cancer that develops in the melanin-producing cells of the eye. But, what we don't know is why there are so many cases happening so suddenly in the same pockets of the country. It sounds like an episode of House M.D., and even experts are stumped. "When this was first going on, there were people looking into the cause of it , the coincidence, and the geographic nature," says Brian Marr , MD, who runs a comprehensive clinic for ocular melanoma at NewYork-Presbyterian/Columbia University Medical Center. "Really, it's been kind of baffling and a little bit peculiar."