What is Melanoma of the Eye?

Cancer can develop in the eye or in nearby structures, such as the eyelids or orbit. Tumors of the eye are most often metastatic tumors that have spread from other parts of the body. The most common primary cancers of the eye are melanoma of the eye (uveal/intraocular melanoma) and retinoblastoma. In adults, melanoma of the eye is the most frequently diagnosed primary eye cancer, and forms in the uvea (middle layer of the eye) from pigment-producing cells called melanocytes. Melanocytes are found mainly in the skin and make the pigment that gives your skin its color, but they can also be found in other places such as the eyes and hair.

Intraocular melanoma may start in the iris, choroid or ciliary body, all of which are located in the uvea, the middle layer of the eye.

• Iris - The iris is the colored part of your eye (which give you "eye color"). The pupil is a small opening in the middle of the iris that lets light into the eye.
• Choroid - The choroid is the thin middle layer of the wall of the eye that delivers blood and nutrients to the eye.
• Ciliary Body - The ciliary body is made up of muscles that change the shape of your lens and help your eye focus.

About 80-90% of all melanomas of the eye start in the choroid, which contains melanocytes, the same pigment-producing cells found in the skin. About 10-20% of other uveal melanomas begin in the iris or ciliary body. Melanomas of the iris are usually easiest to diagnose because they often start on a pre-existing spot on the iris that suddenly begins to mutate. Melanomas of the iris are also usually slow-growing, but can spread to other organs if undetected and untreated.