Tests for Eye Cancer

Eye exam

Examination of the eye by an ophthalmologist (a medical doctor specializing in eye diseases) is often the most important first 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.
• To get a more detailed view than with a direct ophthalmoscope, an indirect ophthalmoscope or a slit lamp may be used. With either instrument, the doctor looks into your eye through a stronger magnified lens, but the slit lamp tends to have more magnification and sits still on a platform in front of you. With an indirect ophthalmoscope, the doctor has you recline a bit, opens your eye, and holds the magnifying lens very close to it while a bright light shines into the eye.
• A gonioscopy lens is a specially mirrored lens that is placed on the cornea (the outer part of the eye) after it is numbed. It can be used to look for tumor growth into areas of the eye that would otherwise be hard to see.

Even if you recently had an eye exam, if you start to have any symptoms, 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 such as imaging tests or other procedures might be done to confirm the diagnosis.

Imaging tests

Imaging tests use sound waves, x-rays, or magnetic fields, or radioactive particles to create pictures of the inside of your body. These tests might be done for a number of reasons, including:

• To help find a suspicious area that might be cancer
• To help determine the stage (extent) of the cancer
• To help show if treatment is working
• To look for possible signs of cancer coming back after treatment

Ultrasound

Ultrasound is a very common test used to help diagnose eye melanomas. Ultrasound uses sound waves and their echoes to make pictures of internal organs or masses. For this test, a small wand-like instrument is placed up against the eyelid or eyeball, sends sound waves through the eye, and picks up the echoes as they bounce off the organs. The echoes are 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. If you have already been diagnosed with eye melanoma, an ultrasound of your abdomen may be done to look for tumors in the liver, which is a common site of spread of this cancer.

Ultrasound biomicroscopy (UBM): This is a special type of ultrasound that uses high-energy sound waves to create very detailed images of the front parts of the eye.

Optical coherence tomography (OCT)

This test is similar to an ultrasound, but it uses light waves instead of sound waves to create very detailed images of the back of the eye.

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.

Chest x-ray

If you have been diagnosed with eye melanoma, an x-ray of your chest may be done to see if the cancer has spread to your lungs.

Computed tomography (CT) scan

A CT scan combines many x-rays to make detailed cross-sectional images of parts of the body. This scan is sometimes used to see if a melanoma has spread outside of the eye into nearby structures. It may also be used to look for spread of the cancer to distant organs such as the liver.

Magnetic resonance imaging (MRI) scan

MRI scans are particularly useful for looking at eye tumors and spread of tumor outside the eye orbit in places like the liver. MRIs provide detailed images of soft tissues in the body, but use radio waves and strong magnets instead of x-rays.

Biopsy

For most types of cancer, the diagnosis is made by removing a small piece of the tumor and looking at it in the lab for cancer cells. This is known as a biopsy.

A biopsy is often not needed to diagnose eye melanomas because almost all cases can be accurately diagnosed by the eye exam and imaging tests. Sometimes, a biopsy may be useful to check for certain gene mutations (changes) that can predict outcomes (prognosis) as well as help choose targeted drugs for your cancer. Also, certain eye melanomas can spread for many years before they are diagnosed so doing a biopsy of a worrisome area early may be helpful.

If a biopsy is needed, it can be done either with sedation and local anesthesia (numbing medicine) or while a person is under general anesthesia (in a deep sleep). Different types of biopsies can be done for eye melanoma depending on where it is located including:

• A FNA (fine needle aspiration): Using a thin needle to remove a small sample of aqueous humor (the liquid between the cornea and the lens)
• An incisional or excisional biopsy (cutting out either part of or all of the tumor)
• A fine needle biopsy of the tumor: Cells from the tumor are sucked up into a syringe through a small needle and examined in the lab. 

Newer techniques help to lower the chances of tumor cells leaking and spreading along the needle path during these biopsies so the cancer doesn't spread within or outside the eye.

While most people with melanoma of the eye are treated without having a biopsy first, your doctor may recommend a biopsy depending on your specific situation. They can discuss the risks and benefits of the procedure they feel is best for you. Some doctors have started using biopsies to get a sample of the tumor for gene testing (DecisionDx-UM). They have found that certain patterns of genes in tumor cells are a good way to tell if an eye melanoma is likely to spread. Based on these gene patterns, a little more than half of eye melanomas are shown to be Class 1 (1A or 1B) tumors which have a low risk of spreading. The remaining eye melanomas fall into the Class 2 category, which have a very high risk of spreading. See What's New in Eye Cancer Research? for more information.

Liquid biopsy

A new type of biopsy called a liquid biopsy is being looked at more often. Instead of having to make a cut or put a needle into the eye, melanoma tumor cells can be collected from a blood sample. These cancer cells can then be tested for certain traits, including genetic changes, that can help predict how likely the cancer is to spread or come back after treatment.. Liquid biopsies might help diagnose tumor spread earlier, or help the doctors know if treatment is working. This could be very helpful in people who did not have a biopsy of the tumor and want to preserve their vision. However, the equipment needed for this test is not readily available so this type of biopsy is not done routinely and is mainly done as part of a clinical trial.

Blood tests

Blood tests can’t be used to diagnose melanoma of the eye, but they may be done once a diagnosis is made.

Liver function tests

If you have been diagnosed with eye melanoma, your doctor may order blood tests to see how well your liver is working. Abnormal test results can sometimes be a sign that the cancer has spread to the liver.