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

How is eye cancer diagnosed?

If you have an abnormal area on your eye that may be cancerous, your doctor will examine it and may do tests to find out if it is melanoma or another eye disease.

If you are seen by your primary doctor and eye cancer is suspected, you may be referred to one ophthalmologista doctor specializing in eye diseases who will take a closer look at the area.

There are many tests used to diagnose eye melanoma. Not everyone needs all the tests described here. The tests you may need depend on:

• The type of cancer that is suspected
• Your signs and symptoms
• Your age and general health
• The results of previous medical tests

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

Eye examination

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

• Ask if you have symptoms
• Check your vision and eye movements
• Look for enlarged blood vessels on the outside of the eye, which could be signs of a tumor inside the eye

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

• ONE direct ophthalmoscope is a handheld instrument that has a light and a small magnifying lens.
• An indirect ophthalmoscope has a stronger magnifying lens. The doctor makes you lean back a little, opens your eye and holds the magnifying lens very close to him while shining a bright light into the eye.
• ONE slit lamp has even more magnification. It sits quietly on a platform in front of you.
• ONE gonioscopy lens is a special mirrored lens that is placed on the cornea (the outer part of the eye) after it is anaesthetized. It can be used to look for tumors in areas of the eye that would otherwise be difficult to see.

If an eye exam suggests that you may have eye cancer, more tests, such as imaging tests or other procedures, may 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 may be done for a variety of reasons, including:

• To help find a suspicious area that may be cancerous
• To help decide stage (extent) of the cancer
• During treatment to help show if the treatment is working
• After treatment, to look for possible signs of the cancer returns

Ultrasound of the eye

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

For this test, a small wand-like instrument is placed 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 in diagnosing eye melanomas because they tend to look a certain way on ultrasound. Using this test, doctors can confirm a diagnosis of melanoma in 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 highly detailed images of the front parts of the eye.

Abdominal ultrasound

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

Optical Coherence Tomography (OCT)

This test is similar to an ultrasound, but it uses light waves instead of sound waves to create highly 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 your arm. Pictures are then taken of the back of the eye using a special light that causes the dye to 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 scan may 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

ONE CT scan combines many X-ray images 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 liver.

Biopsy for eye cancer

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

A biopsy is often not necessary 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 may still be necessary in some situations if the results of exams and tests are not clear.

Even if eye melanoma has already been diagnosed, a biopsy may 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 can affect a person’s treatment options (including if they are eligible for certain clinical trials), as well as how often they need to 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 may be performed for eye melanoma, depending on where the abnormal area is in the eye:

• FNA (fine needle aspiration): Use a thin, hollow needle attached to a syringe to remove a small sample of the fluid in the eye and/or cells from the tumor
• Incisional biopsy: Excision of part of the tumor
• Excisional biopsy: Removal of 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 path of the needle, so the cancer doesn’t spread inside or outside the eye.

Testing of biopsy (or surgery) samples

Before uveal melanomatests that look at specific 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).

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

Gene expression profiling: These tests look at patterns of genes in the cells. For example DecisionDx-UM tests look 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 of the cancer growing and spreading. They can also affect how closely the person is monitored during and after treatment.

Before your treatment begins, talk to your doctor about the risks and benefits of getting 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

ONE liquid biopsy is a newer way to collect cancer cells for testing without having to cut or stick 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 routinely performed yet for eye cancer. For more on this, see What’s new in eye cancer research?