How to test for it

Below is a rather good information video "IF I HAD A MOLE IN MY EYE" from Dr. Carol L. Shields Ocular Oncology Service Wills Eye Institute Philadelphia Pa USA. 

How Is Melanoma of the Eye Diagnosed?

Certain signs and symptoms might suggest that a person could have an eye melanoma, but tests are needed to confirm the diagnosis. Signs and symptoms of eye melanoma Many people with eye melanoma don’t have symptoms unless the cancer grows in certain parts of the eye or becomes more advanced.

Signs and symptoms of eye melanomas can include:

• Problems with vision (blurry vision or sudden loss of vision)
• Floaters (spots or squiggles drifting in the field of vision) or flashes of light Visual field loss (losing part of your field of sight)
• A growing dark spot on the colored part of the eye (iris)
• Change in the size or shape of the pupil (the dark spot in the center of the eye)
• Change in position of the eyeball within its socket
• Bulging of the eye
• Change in the way the eye moves within the socket
• Pain is rare unless the tumor has grown extensively outside the eye. In such cases, bulging or a change in the position of the eye may also be noted.

Other, less serious conditions can also cause many of these symptoms. For example, floaters can be a normal part of the aging process. Still, if you have any of these symptoms, it’s important to see a doctor right away so the cause can be found and treated, if needed. Eye exam Examination of the eye by an ophthalmologist (a medical doctor specializing in eye diseases) is often the most important step in diagnosing melanoma of the eye. The doctor will ask if you are having any symptoms and check your vision and eye movement. The doctor will also look for enlarged blood vessels on the outside of the eye, which can be a sign of a tumor inside the eye. The ophthalmologist may also use special instruments to get a good look inside the eye for a tumor or other abnormality. You may get drops in your eye to dilate the pupil before the doctor uses these instruments.

An ophthalmoscope (also known as a direct ophthalmoscope) is a hand-held instrument consisting of a light and a small magnifying lens. An indirect ophthalmoscope and a slit lamp is more like a large microscope. For this exam, you sit down and rest your chin on a small platform, while the doctor looks into your eye through magnified lenses. This exam can often give a more detailed view of the inside of the eye than the direct ophthalmoscope.

A gonioscopy lens is a specially mirrored lens that is placed on the cornea (the outer part of the eye) after it is numbed. This lets the doctor see the deep structures in the angle of the front of the eye near the iris. It can be used to look for tumor growth into areas of the eye that would otherwise be hard to see. Most of the time if a person has an eye melanoma, a doctor can make the diagnosis with just an eye exam.

In some cases, imaging tests such as ultrasound may be needed to confirm the diagnosis. Very rarely a biopsy will also be needed. Some people might have a benign tumor in the eye called a choroidal nevus, which can sometimes be mistaken for an eye melanoma. A small number of these will eventually turn into melanomas. If your ophthalmologist spots one of these, he or she will likely advise regular eye exams to see if it grows. Even if you recently had an eye exam, if you start to have any of the symptoms listed above, get another exam. Sometimes these tumors are missed or grow so fast that they weren’t there when you were last examined. If an eye exam suggests you might have eye cancer, more tests will likely be needed. These might include imaging tests or other procedures. Imaging tests Imaging tests use sound waves, x-rays, or magnets to create pictures of the inside of your body. Imaging tests may be done for a number of reasons, including to help find a suspicious area that might be cancer, to learn how far cancer might have spread, or to help determine if treatment is working. Ultrasound (echography): This is a very common test for helping to diagnose eye melanomas. Ultrasound uses high-frequency sound waves to make pictures of parts of the body. For this test, a small wand-like instrument is placed up against the eyelid or eyeball, and sound waves are sent through the eye. The instrument picks up the pattern of echoes that comes back, which is converted into an image on a computer screen. This test is especially useful for diagnosing eye melanomas because they look a certain way on ultrasound. Using this test, doctors can confirm a diagnosis of melanoma of the eye in most cases. This test can also show the location and the size of the tumor. Ultrasound biomicroscopy (UBM) is a special type of ultrasound that uses sound waves at even higher frequency to image the front parts of the eye. Optical coherence tomography (OCT) is a similar type of test that uses light waves instead of sound waves to create very detailed images of the back of the eye. If you have already been diagnosed with eye melanoma, an ultrasound may be done of your abdomen to look for tumors in the liver, which is a common site of spread of this cancer. Fluorescein angiography: For this test, an orange fluorescent dye (fluorescein) is injected into the bloodstream through a vein in the arm. Pictures of the back of the eye are then taken using a special light that makes the dye fluoresce (glow). This lets the doctor see the blood vessels inside the eye. Although melanomas don’t have a special appearance with this test, some other eye problems do. Doctors can use this method to tell if something is not a melanoma. This test can also be done using a special green dye to look at the blood vessels. This is known as indocyanine green (ICG) angiography.