Melanoma is a kind of cancer that develops in the cells that give your skin, eyes, and hair their color (they make a pigment called melanin). This cancer is usually on the skin, but it also can happen in your eyes. When it does, it's called ocular melanoma.
It's the most common form of eye cancer in adults, but it's still rare. Your odds of getting it are about 6 in 1 million. It can cause vision problems and can be serious if it spreads to other organs.
Doctors don't know exactly what causes ocular melanoma. As with skin cancer, people with fair skin, blond or red hair, and light-colored eyes are more likely to get it. But, unlike skin cancer, there's no hard evidence that links ocular melanoma to ultraviolet rays, the kind you're exposed to from sunlight or a tanning bed.
People with something called atypical mole syndrome have a greater risk of developing melanoma of the skin and also may be more likely to get ocular melanoma. This condition can cause more than 100 moles to form on a person's body, some with abnormal shape and size.
Scientists are looking into whether a higher risk for ocular melanoma can be passed from parents to their children.
The cancer usually develops in the middle layer of the eyeball, which holds the blood vessels that feed your inner eye. You may not notice any symptoms at first. But as a tumor grows, it can cause floating black spots, light flashes, or loss of eyesight. It sometimes changes the shape of your pupil (the dark circle in the middle of your eye).
In other cases, the tumor forms on the iris, the part that gives your eye its color. If this happens, it's easier to spot early. Between 2% and 5% of people have a tumor in the conjunctiva -- the moist membrane that covers your eye.
Doctors often notice a melanoma during a routine eye exam because the tumors usually are darker than the area around them or leak fluid. Your doctor may want to do additional tests:
- Ultrasound: High-frequency sound waves are used to make images of the inside of your eye.
- Fluorescein angiography: Dye is put in your bloodstream through a vein in your arm, and it goes up to your eye. Your doctor then uses a special camera to take pictures of the inside of your eye. This can help him find any blockage or leak.
In rare cases, when these tests don't give a definite answer, your doctor might take some tissue from your eye to get a closer look under a microscope. This is called a biopsy.
A small tumor might not have to be treated right away. Your doctor may just want to check it regularly to see if it grows or causes problems.
If caught before it spreads outside the eye, most ocular melanomas can be treated successfully. Your treatment may include:
- Radiation. The most common form uses a shield shaped like a small bottle cap to hold radioactive seeds against the outside of your eyeball over the tumor. This is called a plaque, and it's put in and taken out with surgery. It stays in place about 4 days. Most people say it doesn't bother them much. Another form of radiation treatment uses a machine that hits the tumor with radioactive particles. The treatment is usually spread over several days.
- Lasers. Your doctor uses infrared light to kill a small tumor and seal off the nearby blood vessels to keep the cancer from spreading. This typically involves sending a laser beam through your pupil at low power so it can attack the cancer cells without damaging your eye.
- Surgery. In some cases, your doctor might have to take out part of your eye to remove the tumor. Most tumors in the iris are treated this way. If a tumor is big enough, your doctor might have to remove the eye and replace it with a prosthetic eye to provide a normal appearance.
Your doctor probably will recommend you get regular CT scans or MRIs to make sure the cancer hasn't spread. A CT scan (computerized tomography) takes X-rays from different angles and puts them together to show a more complete picture. An MRI (magnetic resonance imaging) uses powerful magnets and radio waves to make detailed images.
Your doctor will focus on your liver, since that's where a new tumor is most likely to start. If it has, the earlier it's found, the more choices you have for treatment.
Your treatment may damage your vision, so you also may need to see an eye doctor (ophthalmologist) regularly.