Ocular melanoma is rare, affecting approximately five in a million people; about 200 cases are diagnosed per year in Canada. Like other melanomas, it begins in melanocytes – the cells that produce the pigment melanin that colours the skin, hair, and eyes, as well as forms moles. While it represents only 5% of melanomas, ocular melanoma is rapid and aggressive, accounting for 9% of melanoma deaths. Also referred to as uveal melanoma, ocular is a more inclusive term; 90% of primary ocular melanoma develops in the choroid.
There are no established risk factors for ocular melanoma, but it often occurs in blue-eyed, fair-skinned people over sixty years old. Treatment can be successful if the tumours in the eye are caught early. Around 50% of tumours will metastasize, usually in two to five years. Metastasis is to the liver in approximately 90% of these cases, but can also occur in the lungs, bones, brain or abdomen.