Eye, or ocular, melanoma is the most common type of eye cancer. It normally affects the uvea, the vascular layer of the eye between the retina and the white of the eye.
It is also known as uveal melanoma. Tumors develop in the melanocytes, the pigment-producing cells within the uvea that give color to the eye.
Most melanomas affect the skin, but some develop in other parts of the body, including the eye.
If cancer starts in the eye, this is primary eye cancer. If the eye melanoma starts elsewhere in the body and spreads to the eye, it is called secondary eye cancer.
Eye cancer is usually secondary, and 9 out of 10 eye melanomas start in the skin.
The American Cancer Society estimate that, in 2017, there will be 3,130 new cancers of the eye and the eye’s orbit in the United States (U.S.), and that 330 people will die of such cancers.
It can happen at any age, but it becomes more likely as people get older.
Eye melanoma may cause vision problems, or there may be no symptoms.
Some patients may experience no symptoms, while others may have light flashes, blurring of vision, or see dark spots in their field of vision.
The following signs and symptoms are possible:
a dark spot in the iris that gets bigger
a displacement of the eye within the eye socket
seeing flashing lights
poor or blurry vision or loss of peripheral vision in one eye
There may also be floaters, or small specks or squiggles that move about in the patient’s field of vision. Floaters may be seen more clearly when looking at a plain background, such as a blank wall. They may appear as tiny dots, circles, lines, clouds, or cobwebs.
Floaters are common, especially as people age, and they do not necessarily indicate cancer.
Rarely, pain in or around the eye can be a sign of eye melanoma.
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Experts are not sure what the exact cause of ocular melanoma is, but genetic factors are believed to play a role in cells becoming cancerous.
Scientists have found links between eye cancer and some genetic changes, but it remains unclear exactly where these changes occur, or if they cause cancer to develop.
Taking the correct precautions when exposed to the sun may reduce the risk of eye melanoma.
Exposure to ultraviolet (UV) light: Exposure to UV light, for example from sunshine, may increase the risk, but research has not confirmed this.
Dysplastic nevus syndrome: In this condition, a person develops atypical moles, known as dysplastic nevi, which look different from ordinary moles. They have irregular borders, may be mixed in color, and appear in clusters. Dysplastic nevi are more likely to develop into malignant melanoma than ordinary moles.
Genetic factors: Some chromosomal abnormalities, such as those found on chromosome 3, increase the risk of melanoma spreading from the eye to other parts of the body.
Ethnicity: It is most likely to affect white people.
Early detection and treatment of ocular melanoma are crucial for effective treatment. Having regular eye tests with an ophthalmologist, or eye doctor, is the best way to protect your eyes.
The doctor examines the outer part of the eye, looking out for enlarged blood vessels. This may indicate a number of eye conditions, including a tumor. The ophthalmologist also examines the inside of the eye.
Ophthalmoscopy is used to examine the inside of the eye, including the retina, the optic nerve, and the lens. This procedure can be direct or indirect.
Indirect ophthalmoscopy uses a head lamp to shine a very bright light into the eye.
Direct ophthalmoscopy uses an ophthalmoscope, a device consisting of a concave mirror and battery-operated light. The operator uses a single eyepiece to look into the eye.
The ophthalmologist may give medication to the patient to dilate the pupils and enlarge the opening into the structures of the eye.