The threat of melanoma – the deadliest form of skin cancer – is reason enough for sun-worshippers to slather on the sun screen.

But did you know that melanoma can occur in the eye?

Ocular melanoma (OM) is much rarer than melanomas of the skin. About 2,000 Americans are diagnosed with OM each year. It often goes undetected, as the most common place it develops is in tissue surrounding the back of the eye (the choroid layer).

Like skin melanomas, OM starts in pigment cells called melanocytes that give color to the eyes. Unlike skin melanoma, which is closely linked to UV light exposure from the sun or tanning beds, there is no certainty about what causes OM. People whose skin burns easily – those with a fair complexion, blue or green eyes and fair or red hair – are most at risk for OM. But having been diagnosed with a skin melanoma does not necessarily increase one’s risk for developing OM.

Once diagnosed with OM, patients are most frequently treated with lasers, radiation or by removing the eye. Still, in about half of patients with OM, the cancer will spread within 10 to 15 years of diagnosis, most often to the liver. Once it spreads, this metastatic OM becomes life-threatening. Current immunotherapy drugs making headlines for progress against skin melanomas are far less effective for metastatic OM, pointing to a need for further research to improve patient outcomes.

Moffitt’s clinical research efforts are focused on OM’s liver metastases and how they can be controlled. Dr. Jonathan Zager, director of Regional Therapies in Cutaneous Oncology and Sarcoma at Moffitt Cancer Center, heads up an international clinical trial at some 40 locations worldwide to address liver tumors that develop when OM spreads. The FOCUS trial involves a surgical procedure called PHP, percutaneous hepatic perfusion.

PHP isolates blood flow to and from the liver, allowing for high-dose heated chemotherapy to be administered directly to the liver through a catheter.  The chemotherapy-laden blood is filtered outside the body and returned to the patient via a separate catheter. Zager said the procedure has been very effective in treating liver tumors in previous trials.

So is there any way to protect against OM? Dr. Zeynep Eroglu, medical oncologist in Moffitt’s Department of Cutaneous Oncology, noted that most of OM’s known risk factors are beyond our control. “While this is a very rare tumor overall, it is more common in patients with certain hereditary genetic abnormalities, or those with fair skin and blue eyes,” said Eroglu.

  Limiting sun or UV exposure in this population is already wise for skin melanoma prevention, and use of UV-protective sunglasses can’t hurt for ocular melanoma as well. She also advises:

• Those with abnormalities in their eyes, like hyperpigmentation on the eyelids, should be followed by an ophthalmologist
• Your physician should be aware of any family history of OM or inherited skin conditions like dysplastic nevus syndrome (abnormal moles)
• Changes such as a visible dark spot on the eye, the shape of the pupil, pain in one eye, blurred or distorted vision or the sensation of flashing lights – all possible symptoms of OM - warrant a talk with your eye doctor