An incredibly rare eye cancer called ocular melanoma that only affects six people in one million has stumped doctors in the towns of Auburn, Alabama and Huntersville, North Carolina, who have had patients with the condition.
Three friends who were students at Auburn University have developed the cancer, Newsweek reports. Multiple more people have since messaged a Facebook page for former students to say that they have contracted the condition. Doctors have also diagnosed 18 more people in Huntersville. And while unusual, doctors are still unsure if they should call these cases “clusters.”
Ashley McCrary, one of the students, was shocked when she was diagnosed with ocular melanoma after her friends Juleigh Green and Alison Aldred both lost their eyes to the disease. She said,
What’s crazy is literally standing there, I was like, ‘Well, I know two people who’ve had this cancer.’
Cells that produce pigment tan the skin, tint hair color, and are responsible for eye color. These cells are well-known to be sensitive, and are at extreme risk for skin melanoma. But melanoma also affects the mouth, intestines, and eyes. Pigment-producing cells in people’s eyes can develop ocular melanoma.
The eyes are made up of three layers, and according to the American Academy of Ophthalmology, cancerous cells tend to group together in the middle of these layers, where they are difficult to find.
Marlana Orloff, an oncologist from the Sidney Kimmel Cancer Center in Philadelphia, said, “Most people don’t know anyone with this disease. We said, ‘OK, these girls were in this location, they were all definitively diagnosed with this very rare cancer—what’s going on?’”
The exact cause of ocular melanoma is still unknown, but factors such as sun exposure, light eye color, older age and paler skin are usually associated with the disease. Environmental factors may also be involved, but doctors are not yet sure about which specific thing to blame.