Tests for Eye Cancer

Most eye cancers are melanomas (also known as ocular melanomas or intraocular melanomas). Some of these might be brought to a doctor’s attention because of signs or symptoms a person is having. But not all eye cancers cause symptoms, and sometimes these cancers are found during eye exams or on tests.

How is eye cancer diagnosed?

If you have an abnormal area on your eye that might be cancer, your doctor will examine it and might do tests to find out if it is melanoma or some other eye condition.

If you’re being seen by your primary doctor and eye cancer is suspected, you may be referred to an ophthalmologist, a medical doctor who specializes in eye diseases, who will look at the area more closely.

There are many tests used for diagnosing eye melanoma. Not everyone will need all of the tests described here. The tests you may need will depend on:

• The type of cancer suspected
• Your signs and symptoms
• Your age and general health
• The results of any earlier medical tests

If eye cancer is found, more tests might be done to learn more about it and whether it has spread to other areas of the body.

Eye exam

Usually, the first step in diagnosing eye melanoma is an exam by an ophthalmologist. The doctor will:

• Ask if you’re having symptoms
• Check your vision and eye movement
• Look for enlarged blood vessels on the outside of the eye, which can be a sign of a tumor inside the eye

To get a good look inside the eye, the ophthalmologist may dilate the pupil with eyedrops and use special tools:

• A direct ophthalmoscope is a hand-held instrument that has a light and a small magnifying lens.
• An indirect ophthalmoscope has a stronger magnifying lens. 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 slit lamp has even more magnification. It sits still on a platform in front of you.
• 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 tumors in areas of the eye that would otherwise be hard to see.

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 for eye cancer

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

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

Ultrasound of the eye

Ultrasound is a very common test to help diagnose eye melanomas. It uses sound waves and their echoes to make pictures of organs and structures in the body.

For this test, a small wand-like instrument is placed up against the eyelid or eyeball. It sends sound waves through the eye and picks up the echoes as they bounce back. The echoes are converted into an image on a computer screen.

This test is very useful for diagnosing eye melanomas because they tend to 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 size of the tumor.

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.

Abdominal ultrasound

If you have already been diagnosed with eye melanoma, an ultrasound of your abdomen (belly) may be done to look for tumors in the liver, which is a common site of spread of this cancer.

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 your 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.

Magnetic resonance imaging (MRI)

MRI scans use radio waves and strong magnets instead of x-rays to make detailed pictures of the inside of the body. MRI can be very helpful when looking at eye tumors. It can sometimes help tell if an abnormal area is a melanoma, as well as show how far the tumor has grown into nearby structures.

If eye melanoma is found, an MRI might also be done on other parts of the body to look for spread of the cancer to places like the liver.

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 look for spread of the cancer to other parts of the body, such as the lungs or the liver.

Biopsy for eye cancer

For most cancer types, the diagnosis of cancer 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 they can usually be diagnosed based on the results of a thorough eye exam and imaging tests. But a biopsy might still be needed in some situations if the results of exams and tests aren’t clear.

Even if eye melanoma has already been diagnosed, a biopsy might still be done to check the cancer cells for certain gene or chromosome changes that can help predict the chance of the cancer spreading to other parts of the body. This might affect a person’s treatment options (including if they’re eligible for certain clinical trials), as well as how often they should be seen after treatment. (See below for more on this.)

While many people with melanoma of the eye are treated without having a biopsy first, your doctor may advise a biopsy depending on your specific situation. They can discuss the risks and benefits of the procedure with you.

If a biopsy is needed, it can be done either with sedation and local anesthesia (numbing medicine) or while you are under general anesthesia (in a deep sleep).

Different types of biopsies can be done for eye melanoma, depending on where the abnormal area is in the eye:

• FNA (fine needle aspiration): Using a thin, hollow needle attached to a syringe to remove a small sample of the liquid in the eye and/or cells from the tumor
• Incisional biopsy: Cutting out part of the tumor
• Excisional biopsy: Removing the entire suspicious area. This type of biopsy is commonly used to diagnose conjunctival eye melanoma.

Newer biopsy techniques can help lower the chances of tumor cells leaking or spreading along the needle path, so the cancer doesn't spread within or outside the eye.

Testing of biopsy (or surgery) samples

For uveal melanoma, tests that look at certain genes and chromosomes inside the cancer cells can provide information about how likely the cancer is to spread from the eye to other parts of the body. Tests may include:

Cytogenetic testing: This type of test looks for changes in certain chromosomes, including chromosomes 3, 6, and 8. This can help predict how likely a uveal tumor is to spread (metastasize). For example, uveal melanomas that spread often have only one copy of chromosome 3 (known as monosomy 3).

Testing for specific gene changes: Mutations in the BAP1 gene, which is located on chromosome 3, are also linked with a high risk of metastasis. Mutations in the SF3B1 and EIF1AX genes are linked with a lower risk of spread.

Gene expression profiling: These tests look at patterns of genes within the cells. For example, the DecisionDx-UM test looks for certain patterns that show how likely an eye melanoma is to spread:

• Class 1 (1A or 1B) tumors have a low risk of spreading.
• Class 2 tumors have a high risk of spreading.

These tests can help a person understand their risk for the cancer growing and spreading. They might also influence how closely the person is monitored during and after treatment.

Before your treatment begins, talk with your doctor about the risks and benefits of having one of these tests and what the results might mean for your care. 

See What's New in Eye Cancer Research? for more information.

Liquid biopsy

A liquid biopsy is a newer way to collect cancer cells for testing without having to make a cut or put a needle into the eye. Instead, melanoma cells can sometimes be collected from a blood sample. But liquid biopsies are still being researched and  not done routinely yet for eye cancers. For more on this, see What’s New in Eye Cancer Research?