Many people are confused by the melanoma aspect of this type of eye cancer, as melanoma is most commonly associated with skin. Melanomas develop from melanocytes, cells that contain the dark pigment (melanin) that defines our skin coloring. Melanocytes aren't exclusive to the skin -- they can be found in the hair, the eyes, and the lining of some organs.
What Causes Ocular Melanoma?Like many other types of cancer, we aren't quite sure what causes ocular melanoma, but there is suspicion that it is related to exposure to the UV rays of the sun. This theory has yet to be proven, however.
Even though the cause of ocular melanoma has yet to be pinpointed, researchers have identified risk factors for the disease. Risk factors for ocular melanoma include:
- being fair skinned or having a light hair color and eye color
- having dysplastic nevus syndrome, a condition that causes abnormal moles
- having oculodermal melanocytosis, a rare condition that causes increased and abnormal pigmentation of the eye and skin around the eye
Symptoms of Ocular MelanomaThere are sometimes no noticeable symptoms of ocular melanoma, especially in the early stages. In these instances, melanoma of the eye is usually diagnosed through a routine eye screening by an optician. Ocular melanoma symptoms include:
blurred vision in one eye
floaters (small "floating" spots in your vision field)
change in iris color or dark spot on iris
red and/or painful eye
- loss of peripheral vision
Diagnosing Ocular MelanomaUnlike other types of cancer, a biopsy is not usually needed for most cases of ocular melanoma. One of the first tests most people have is called an ophthalmoscopy, which uses a special scope to get an in-depth view of the eye. It is much like the tool your optician or physician uses to look at your eye. It is noninvasive and is painless.
An ultrasound may also be done to view the eye and surrounding structures. Numbing drops are given before the scan to prevent any discomfort. You may be asked to look in different directions to allow for different angles of viewing. Eye ultrasounds generally take about 15 minutes or less.
Other tests, like an MRI or CT scan, may be done if it is suspected that the cancer has spread beyond the eye. The liver is common site of metastasis for ocular cancer.
Treatment of Ocular MelanomaTreatment of ocular melanoma is based on what part of the eye is affected and whether it has metastasized to other parts of the body. Surgery is a common method of treatment that involves removing part or all of the eye.
Removal of the eye (enucleation) may be necessary in some cases of large tumors when other treatment methods are not suitable. An artificial eye can be created in most cases. Prosthetic eyes today are much more realistic than in the past. They are created by talented, trained individuals called ocularists. It generally takes anywhere from 4 to 6 appointments to be fitted for a prosthetic eye and for it to be placed. Quality and artistic talent are two important characteristics to consider when choosing an ocularist.
Radiation therapy is also a common method treatment of ocular melanoma. It may be the sole treatment or done after surgery. There are two types of radiation therapy: external and internal. Both use specific types of energy to disrupt the activity of cancer cells to eliminate them and prevent them from undergoing cell division.
External radiation delivers radiation from a specialized machine that targets the tumor site externally. This method of radiation is specific and limits the damage to surrounding tissue.
Internal radiation (brachytherapy), often called plaque therapy when referencing the treatment of ocular melanoma, uses a radioactive "seed" or "plaque" that is implanted near the tumor site to deliver therapy. Normally, it remains implanted for about 7 days and is then removed.
Radiation therapy is effective against ocular melanoma, but does not come without side effects. Red, dry eyes are a common side effect. Cataracts sometimes result from therapy, but surgery may be an option to remove them. Eyelash loss and shortening may also occur. Less commonly, radiation therapy can cause optic nerve damage, glaucoma, and abnormal blood vessels in the retina.