What is ocular melanoma?
Ocular melanoma is a type of cancer in the cells that have pigment within the eye. Just as melanoma can develop on the skin, it can also develop inside of the eye. Although it is the most common form of eye cancer in adults, ocular melanoma is very rare.
Ocular melanoma usually forms in the part of the eye that is not visible when looking into a mirror, which can make it challenging to detect. It also doesn’t typically cause any early signs or symptoms.
What causes ocular melanoma?
It is not clear what causes eye melanomas to develop. However, it’s known that people born with certain growths in or on the eye, as well as those with lighter coloured eyes, are more at risk of developing ocular melanoma.
What are the symptoms of ocular melanoma?
The melanoma usually develops in the middle layer of the eyeball, the choroid, which holds blood vessels that feed and drain some of the structures inside the eyes. It can also form within the iris, the coloured circular structure responsible for controlling light entry to the eye. In its early stages of development, symptoms may not be present. However, as the tumor grows, it can cause:
- Floating black spots
- Light flashes
- Blurred or distorted vision
- Change in the shape of the pupil
Ocular melanoma differs from a nevus (or mole/freckle), which is benign and not cancerous. Ocular melanoma can spread outside the eye to other parts of the body such as the liver, lungs, and bones.
How is ocular melanoma detected?
Ocular melanoma can be detected with a dilated eye exam by an optometrist. Because ocular melanoma may not cause any obvious signs or symptoms at first, the disease is often detected during a routine eye exam. This is why it’s important to visit your optometrist on a regular basis.
If your optometrist suspects that you may have ocular melanoma, he or she may recommend more tests to be conducted (for example, an ultrasound and imaging of the back of the eye, and/or referral to an ophthalmologist with experience in treating ocular melanoma.
How is ocular melanoma treated?
Ocular melanoma treatments vary depending on the location and size of the melanoma and your overall general health. Some common treatment options include:
The most common form of radiation therapy uses a shield shaped cap (called a plaque) to hold radioactive seeds against the outside of the eyeball over the tumor. It’s surgically placed on the eye, then removed after approximately four days. Radiation therapy can also be delivered by a machine. The machine sends a beam of radioactive particles to the eye and is performed over a course of several days.
In some cases, surgery may be recommended due to the size and location of the melanoma. The surgery may involve removing the tumor, along with some of the eye’s healthy tissue. In situations where the tumors are larger and cause complications causing eye pain and vision loss, the surgery may involve removal of the entire eye.