How Ocular Melanoma Is Diagnosed

Ocular (eye) melanoma is the most common type of eye cancer. A diagnosis of ocular melanoma includes a detailed patient history, an eye examination, and a variety of specialized tests. Eye melanoma is rare: In the United States, the incidence of ocular melanoma is six cases per 1 million people.

In many individuals, ocular melanoma is discovered during a routine eye examination by an optometrist or ophthalmologist without any symptoms being present.

Optometrist Examining Patient At Clinic

Stevica Mrdja / EyeEm / Getty Images

Self-Checks/At-Home Testing

It's not really possible to diagnose yourself with ocular melanoma. Most eye melanomas form in the part of the eye you can’t view when looking in a mirror, so they can be difficult to detect. That's why it is so important to visit your optometrist for regular checkups.

If you notice any of the following symptoms, check in with your eye doctor who may refer you for further examinations:

  • Having trouble seeing
  • Losing part of your field of vision
  • Seeing flashes of light
  • Seeing spots, squiggly lines, or floating objects (floaters)
  • Having a dark spot on the iris (the colored part of the eye)

Physical Examination

If you have symptoms of eye cancer, you usually start by seeing your primary care physician or optometrist, a doctor who handles primary vision care. The optometrist will ask questions about your past medical history, any medications you are taking, and how long you have had the symptoms. If the doctor suspects you may need further examination, you will be referred to an ophthalmologist, a medical doctor specializing in eye diseases.

The ophthalmologist will examine the outside of your eye, looking for enlarged blood vessels that can indicate a tumor inside your eye.

The ophthalmologist may use special instruments to get a good look inside the eye for a tumor or other abnormality. Drops may be put in your eye to dilate the pupil before the doctor uses the following instruments:

  • An ophthalmoscope, a handheld instrument consisting of a light and a small magnifying lens
  • An indirect ophthalmoscope, or slit lamp, which sits on a platform and provides stronger magnification for a more detailed view
  • gonioscopy lens, a mirrored lens that is placed on the cornea (the outer part of the eye) after it is numbed to look for tumor growth into areas of the eye that would otherwise be hard to view

If an eye exam suggests you might have eye cancer, more tests such as imaging or other procedures might be done to confirm the diagnosis.

Labs and Tests

In some cases, your doctor may recommend a procedure to remove a sample of tissue (biopsy) from your eye to test for cancer.

To remove the sample, a thin needle is inserted into your eye and used to extract suspicious tissue. The tissue is tested in a laboratory to determine whether it contains eye melanoma cells.

An eye biopsy isn't usually necessary to diagnose eye melanoma. Doctors can correctly diagnose more than 95% of ocular melanomas without a biopsy, so this procedure is not needed for most people. 

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

Ocular melanoma that develops in the middle layer of the eye (the uvea) has an approximate 40% risk of metastasizing to the liver within 10 years of diagnosis of the original tumor.

Imaging

You may need a number of imaging tests to determine whether cancer is present in the eye and if it has spread to any other parts of the body (metastasized). Imaging includes:

  • Ultrasound scan: The doctor gently presses a small probe against your closed eyelid and moves it over the skin. This is painless and usually only takes a few minutes. This test is especially useful for diagnosing eye melanomas because they look a certain way on ultrasound. Doctors can confirm a diagnosis of melanoma of the eye with ultrasound in most cases. 
  • Optical coherence tomography: 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: The doctor uses this test to examine the back of your eye. The doctor injects a dye, called fluorescein, into a vein in your arm and then uses a special camera to take photos of the dye as it moves through the blood vessels at the back of your eye.
  • Computed tomography (CT) scan: A CT scan combines many X-ray slices to make detailed cross-sectional images of parts of the body. This scan is sometimes used to see if melanoma has spread outside of the eye into nearby structures. It may also be used to look for the spread of cancer to distant organs, such as the liver.
  • Magnetic resonance imaging (MRI) scan: MRI scans are particularly useful for looking at eye tumors and the spread of tumors outside the eye 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.

After diagnostic tests are done, your doctor will review all of the results with you. If the diagnosis is cancer, these results also help the doctor describe the cancer. This is called staging.

Staging Ocular Melanoma

A staging system is a standard way to describe how far a cancer has spread. Staging is used to determine a treatment plan. The most common systems used to describe the stages of eye cancer are the American Joint Committee on Cancer (AJCC) TNM system and the Collaborative Ocular Melanoma Study (COMS) group classification system.

The AJCC TNM system is based on three key pieces of information. They are:

  • The size and extent of the main tumor (T)
  • The spread to nearby lymph nodes (N)
  • The spread to distant sites (M)

The staging system devised by the COMS group is simpler, and divides eye melanomas into small, medium, and large, such as:

  • Small are between 1 millimeter (mm) and 3 mm in height and between 5 mm and 16 mm across.
  • Medium are between 3.1 mm and 8 mm in height and no more than 16 mm across.
  • Large are more than 8 mm in height or more than 16 mm across.

Differential Diagnosis

Cancer of the eye is rare. Eye conditions that aren't eye cancer can cause symptoms associated with ocular melanoma. These include:

  • Nearsightedness, in which faraway objects are blurry
  • Farsightedness, in which nearby objects are blurry
  • Astigmatism, a condition in which your eye isn't completely round
  • Cataracts, when the lens, a small transparent disc inside your eye, develops cloudy patches
  • Melanocytoma, a benign pigmented tumor
  • Old age can cause eye changes, including floaters

When to Seek Emergency Care

If you have the following symptoms, you should seek emergency care:

  • Bleeding from your eyes or eyelid
  • Vision loss or sudden blindness 
  • Pupils become different sizes and no longer match each other 
  • Problems opening, closing, or moving the eyes 
  • Eyes bulge out 
  • Injuries or trauma to the eyes

A Word From Verywell

If experiencing any changes in your eye or vision, contact your primary care doctor or optometrist, who will likely refer you to a specialist ophthalmologist. Diagnosis is fairly simple and is often minimally invasive.

As eye melanoma is often picked up during routine eye examinations, make sure you attend your regular checkups with your eye doctor so any abnormalities can be found sooner rather than later.

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7 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. American Cancer Society. What is eye cancer? Updated November 2018.

  2. Jovanovic P, Mihajlovic M, Djordjevic-Jocic J, Vlajkovic S, Cekic S, Stefanovic V. Ocular melanoma: an overview of the current statusInt J Clin Exp Pathol. 2013;6(7):1230-1244. PMID: 23826405

  3. American Society of Clinical Oncology. Eye cancer—diagnosis. Updated August 2015.

  4. Grossniklaus HE. Progression of ocular melanoma metastasis to the liver: the 2012 Zimmerman lectureJAMA Ophthalmol. 2013;131(4):462-469. doi:10.1001/jamaophthalmol.2013.2547

  5. American Academy of Ophthalmology. What is optical coherence tomography? Updated June 2021.

  6. American Academy of Ophthalmology. What is fluorescein angiography? Updated June 2021.

  7. American Cancer Society. Eye cancer stages. Updated November 30, 2018.