What is melanoma of the eye?

Melanoma is an aggressive form of cancer that can be life-threatening. Melanoma is a cancer involving melanocytes, the pigment producing cells in your skin. While melanoma typically affects the skin, it can also involve the eye because cells related to melanocytes are also located in the eye.

Melanoma of the eye (also known as uveal melanoma or ocular melanoma) is a rare condition. Research suggests that melanoma of the eye occurs more frequently in people with moles in the eye, moles on the skin, freckles, fair skin color, light eye color, and an increased sensitivity to burning in the sun. Those who are arc welders are also at risk.

As well, people with a disorder known as oculodermal melanocytosis are at a much higher risk for ocular melanoma.

The choroid layer of your eye is where small blood vessels in your eye are located. This is the layer most commonly affected by ocular melanoma.

Melanoma 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
  • iris, the colored part of your eye that helps control how much light is let in
  • 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 (This type of melanoma is thought to be different from ocular melanoma, with its own treatment as well as outlook.)

Although melanoma of the eye is rare, it’s the most common type of eye cancer in adults.

Many people with ocular melanoma have no symptoms, and the condition is often found during a routine eye exam. When present, symptoms can include:

  • changes in your iris
  • flashes of light
  • vision changes, such as blurred vision or loss of certain parts of your vision
  • eye pain

Melanoma of the eye can develop when pigment cells in your eye grow out of control. The cause of uncontrollable cell growth isn’t usually known.

When a cancer is found in the area of the body where it began, it’s known as the primary tumor. Ocular melanoma is a primary tumor since the melanoma has started from cells in the eye.

This type of cancer can occur at any age, but it’s more common in older people with a peak occurrence at around age 70.

This type of cancer seems to affect men and women equally, although some studies have suggested men are more commonly affected. Ocular melanoma is more common in Caucasians.

Metastasis occurs when cancer from one organ or part of your body grows and spreads to another. Melanoma of the eye can spread (metastasize) to other parts of the body, most commonly the liver.

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 some structures of your eye.

If your doctor detects an abnormality in your eye, additional tests may be ordered to evaluate it further. These can include further imaging with a CT scan, MRI scan, or ultrasound. A biopsy may also be recommended.

Once the diagnosis is confirmed, further tests may also include more imaging to look for spreading of the tumor throughout the body, such as a liver ultrasound and liver blood tests. Usually this type of testing is done routinely for people with melanoma of the eye to monitor for metastasis.

Except in specific circumstances, treatment for melanoma of the eye is almost always recommended. The specific type of treatment will depend on several factors such as the size and location of the melanoma within the eye.

The goal of treatment in ocular melanoma is to prevent it from spreading (metastasis). This can be accomplished through the following treatments:

  • surgery to remove the affected eye (This type of procedure, known as enucleation, isn’t as common now that alternative nonsurgical treatments such as radiation may have similar outcomes.)
  • radiation therapy (different types exist)
  • light or laser therapy

Several factors determine the outlook for ocular melanoma. The type of ocular melanoma is very important since iris melanoma has a much better outcome than melanoma of the ciliary body or choroid. The latter have higher chances of metastasis, particularly to the liver, and greatly increase the risk of death.

The chance that melanoma of the eye will metastasize is around 50 percent within 10 years of the diagnosis.

Once metastasis is detected, it isn’t uncommon for the disease to cause death within six months to a year, although people have reportedly survived longer.

Other factors that may affect outlook include the size of the melanoma when detected as well as genetic analysis of the chromosomes of the tumor.

Melanoma of the eye isn’t known to be preventable. It’s currently unclear whether ultraviolet light exposure is related to an increased risk for ocular melanoma.

The only preventive measure you can take now is to avoid arc welding, as this activity is associated with ocular melanoma.

Early detection of ocular melanoma is very important. If your doctor recommends it, routine eye examinations may help with early detection.