Melanoma is an aggressive form of skin cancer that can be life-threatening. Melanoma typically affects the skin, but it can also spread to the eye.

Malignant melanoma of the eye is a rare condition that can occur when your eye has been exposed to too much ultraviolet radiation, or sunlight. The choroid layer of your eye is where blood vessels are stored. This is the layer most commonly affected by malignant melanoma.

The disease can also affect other structures of your eye, including the:

  • ciliary body, which helps lubricate your eye and contains muscles that help your eye focus
  • conjunctiva, which is a thin, transparent tissue that covers the inside of your eyelid as well as your sclera, or the white of your eye
  • iris, the colored part of your eye that helps control how much light is let in
  • orbit, the cavity in your skull that contains your eye

Although melanoma of the eye is rare, it’s the most common type of eye cancer in adults. People with fair skin or blue eyes are most affected by this type of cancer. This type of cancer can also spread to other parts of the body, usually the liver.

Many people with primary malignant melanoma have no symptoms. The condition is often found during a routine eye exam. The symptoms can be quite distinct in those who do develop them. They can include:

  • bulging eyes
  • changes in the color of your iris
  • vision changes, such as blurred vision or double vision
  • red, swollen eyes and pain in your eyes, or both
  • small defects that can be seen on your iris or conjunctiva

Malignant melanoma of the eye can develop when pigment cells in your eye grow out of control. Pigment cells are responsible for your eye color. The cause of uncontrollable cell growth isn’t usually known. Exposure to ultraviolet radiation has been identified as one potential cause of the disease.

Malignant melanoma that begins in your eye is known as a primary tumor. This type of cancer can occur at any age, but it’s more common in people older than the age of 55. This type of cancer affects men and women equally.

Malignant melanoma may result if cancer that develops in another part of your body metastasizes. Metastasis occurs when cancer from one organ or part of your body grows and spreads to another. Metastasis of liver cancer may lead to malignant melanoma. If melanoma develops because of metastasis, it’s considered a secondary tumor.

Malignant melanoma of the eye is usually diagnosed through ophthalmoscopy, an examination of your eye using an ophthalmoscope. This is a device that enables your doctor to see the structures of your eye. If your doctor detects a tumor in your eye, additional tests may be ordered to confirm diagnosis. These can include:

Treatment for malignant melanoma of the eye will depend on the specific type of tumor that you have. If the tumor is small and isn’t growing rapidly, your doctor may not recommend any treatment. Instead, your doctor will monitor your tumor to make sure that it doesn’t grow, spread, or change.

Your doctor may recommend more aggressive treatment if your tumor is large or has the potential to spread to other organs in your body. Malignant melanoma of the eye can be life-threatening if it spreads to other organs.

The goal of treatment is to limit the growth of the tumor and prevent it from spreading. This can be accomplished through the following treatments:

The type of tumor determines the outlook if you have malignant melanoma of the eye. The outlook is quite good if the malignant melanoma is a primary tumor and hasn’t spread to other parts of your body.

With appropriate treatment, a majority of people will survive at least five years after diagnosis. However, treatment may result in vision loss or damage to your eye. In some cases, removal of your eye may be necessary.

If you have secondary malignant melanoma of the eye or a primary tumor that spreads to other organs in your body, the outlook isn’t as favorable. Survival rates decline significantly depending on the other organs that are affected by the cancer.

Secondary malignant melanoma of the eye often results from liver cancer. Five-year survival rates for liver cancer that has spread to distant organs is about 3 percent according to the American Cancer Society.

You can help prevent malignant melanoma of the eye by getting an annual eye exam. Avoiding excessive exposure to sunlight is also helpful. If you’re outdoors, try to wear sunglasses with ultraviolet protection when the sun’s rays are the strongest, which is between 10 a.m. and 2 p.m.