ON THIS PAGE: You will find some basic information about this disease and the parts of the body it may affect. This is the first page of Cancer.Net’s Guide to Eye Melanoma. Use the menu to see other pages. Think of that menu as a roadmap for this entire guide.
About the eye
The eye is the body's organ that collects light and sends messages to the brain. Those messages form a picture. The 3 main parts of the eye are:
Orbit (eye socket)
Adnexal (accessory) structures, such as the eyelid and tear gland
The eye is made up of several key structures: the cornea, conjunctiva, sclera, uvea, retina, and optic nerve. The cornea is the clear outer layer located at the front of the eye. The conjunctiva is the thin skin covering of the sclera, which is the white-colored outer wall of the eyeball. The uveal tract is the blood vessel-rich middle layer of the eye wall. The retina is a delicate and critical structure that is responsible for vision. Like the film in a camera, it lines the inner surface of the eyeball. The retina also sends information from the eye to the brain through the optic nerve. The uvea nourishes the eye. Both the retina and the uvea contain blood vessels.
The 3 main parts of the uvea are:
Iris: The iris is the colored circle at the front of the eye. It controls the amount of light entering the eye.
Ciliary body: The ciliary body is the muscular tissue that produces the watery fluid in the eye. The tissue helps the eye focus.
Choroid: The choroid is a layer of tissue underneath the retina in the back of the eye. It contains connective tissue and nourishes the inside of the eye.
See the Medical Illustrations section for detailed drawings of the eye.
About eye melanoma
Melanocytes are cells that produce melanin, which is a pigment that colors your skin, hair, and eyes. In the eye, melanocytes are located within the uveal tract. Eye melanoma begins when melanocytes change and grow out of control, forming a mass called a tumor. A tumor can be cancerous or benign. A cancerous tumor is malignant, meaning it can grow and spread to other parts of the body. A benign tumor means the tumor can grow but will not spread.
This guide is about primary eye melanoma, which means the tumor started in the eye. This is different from melanoma that spreads to the eye after it started somewhere else in the body, through a process called metastasis.
Eye melanoma is rare. However, it is the most common type of primary eye cancer in adults. After skin melanoma, eye melanoma is the second most common type of melanoma. It accounts for around 3% to 5% of all melanoma cases.
Specially trained ophthalmologists called ocular oncologists can diagnose and treat eye melanoma. They are medical doctors who specialize in the tumors and functions of the eye. Optometrists are another type of eye doctor. They prescribe eyeglasses and contact lenses. They are not medical doctors and are not trained to treat eye melanoma. However, optometrists perform eye exams and sometimes may discover an eye melanoma during a routine exam. Many patients may initially be diagnosed through an optometry exam and then referred to an ocular oncologist.
Eye melanoma is a different disease from melanoma of the skin and other types of melanoma. These include melanomas that develop in the gastrointestinal tract, vagina, the mucous membranes that line the mouth, and other locations around the body. Learn more about melanoma diagnosed in other parts of the body in these separate sections of this website:
Types of eye melanoma
Uveal melanoma. Eye melanoma is often called uveal melanoma. That is because around 95% of all eye melanoma starts in the uvea. In about 50% of people with uveal melanoma, the disease spreads to other parts of the body. Approximately 90% of the time, the melanoma spreads to the liver. It can also spread to other areas, including the lungs, skin, soft tissue, bone, and brain.
There are 3 main subtypes of uveal melanoma:
Choroidal melanoma. More than 85% of uveal melanoma starts in the choroid. These tumors are often larger and are more likely to spread outside the eye compared with iris melanoma (see below).
Ciliary body melanoma. About 5% to 8% of uveal melanoma starts in the ciliary body. Because the ciliary body is located behind the iris, the disease can grow undetected for a longer time than choroidal melanoma or iris melanoma. As a result, the tumor is often larger when diagnosed. Ciliary body melanoma is more likely to spread outside the eye than iris and choroidal melanomas.
Iris melanoma. Iris melanoma is the least common type of uveal melanoma. The disease makes up only 3% to 5% of all uveal melanoma cases. The tumors are often small, grow slowly, and rarely spread outside the eye. They often appear as a growing dark spot on the iris. This makes them easier to see than the other forms of uveal melanoma.
Conjunctival melanoma. Conjunctival melanoma makes up less than 1% of all melanomas. A conjunctival melanoma often looks like a raised, pigmented or non-pigmented spot. The tumor appears most commonly in the bulbar conjunctiva, which is the part of the conjunctiva that covers the sclera.
While conjunctival melanoma is much rarer than uveal melanoma, it may be more aggressive. The disease can spread to nearby areas, like the eyeball, orbit, and regional lymph nodes. The lymph nodes are small, bean-shaped organs located throughout the body that help fight infection. Conjunctival melanoma can also spread to distant areas, including most commonly the lungs. Other common areas of metastasis include the liver, brain, or bones. The disease tends to recur, or come back, after treatment. This type of eye melanoma is not the same as uveal melanoma. As a result, they are treated differently.
Orbital melanoma. Orbital melanoma affects the tissue around the eyeball. Extremely rare, it is the least common type of eye melanoma. As of 2018, which is the most recent data, an estimated 60 cases were reported worldwide. Orbital melanoma can be inactive for a long time before it becomes aggressive.
The next section in this guide is Statistics. It helps explain the number of people who are diagnosed with eye melanoma and general survival rates. Use the menu to choose a different section to read in this guide.