How is eye cancer diagnosed?
Certain signs and symptoms might suggest that a person may have eye cancer, but tests are typically needed to confirm the diagnosis.
Diagnosing melanoma of the eye
Signs and symptoms of eye melanoma
Many patients 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 iris
- Change in the size or shape of the pupil
- 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 except in cases of massive spread 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 may occur as 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.
Examination of the eye by an ophthalmologist (a medical doctor specializing in diseases of the eye) 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 provide 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 (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 provide information on tumor growth into areas of the eye that would otherwise be hard to see.
Most of the time, an eye exam alone can make the diagnosis. In some cases, imaging tests such as ultrasound may be required to confirm the diagnosis. Very rarely a biopsy will also be needed.
Many people 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 have recently had your eyes examined by an ophthalmologist or optometrist, 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 symptoms and/or the results of the eye exam suggest you might have eye cancer, more involved tests will likely be done. These might include imaging tests or other procedures.
Imaging tests use sound waves, x-rays, or magnetic fields 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 cancerous, to learn how far cancer may have spread, or to help determine if treatment has been effective.
Ultrasound: This is an important test for helping to diagnose eye melanomas. Ultrasound is a very common test that uses high-frequency sound waves to take pictures of parts of the body. For this test, which is also known as echography, a small instrument is placed up against the eyeball and high frequency 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 have a specific appearance on ultrasound. Using this test, doctors can confirm a diagnosis of melanoma of the eye in most cases. This test can also tell the doctor 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 of the eye.
If you have already been diagnosed with eye melanoma, ultrasound may also be used to look for tumors in the liver, which is a common site of spread of this cancer.
Fluorescein angiography: This is another test used to help diagnose melanoma of the eye. 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 light that causes the dye to fluoresce (glow). This lets the doctor see the blood vessels inside the eye. Although melanomas do not 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.
When a special green dye is used to look at the blood vessels, this test is known as indocyanine green (ICG) angiography.
Chest x-ray: If you have been diagnosed with eye melanoma, a plain x-ray of your chest may be done to see if the cancer has spread to your lungs. This is very unlikely unless your cancer is far advanced. This x-ray can be done in any outpatient setting. If the results are normal, you probably don't have cancer in your lungs.
Computed tomography (CT or CAT) scan: The CT scan is an x-ray test that produces detailed cross-sectional images of your body. Instead of taking one picture, like a standard x-ray, a CT scanner takes many pictures as it rotates around you. A computer then combines these pictures into detailed images of the part of your body being studied.
CT scans are 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.
Before the scan, you may be asked to drink a contrast solution and/or get an intravenous (IV) injection of a contrast dye that helps better outline abnormal areas in the body. You may need an IV line through which the contrast dye is injected. A blood test that measures kidney function will be done before dye is given, as it can sometimes harm the kidneys. The injection can also cause some flushing (redness and warm feeling). Some people are allergic and get hives or, rarely, more serious reactions like trouble breathing and low blood pressure. Be sure to tell the doctor if you have any allergies or have ever had a reaction to any contrast material used for x-rays.
CT scans take longer than regular x-rays. You need to lie still on a table while the scan is being done. During the test, the table slides in and out of the scanner, a ring-shaped machine that completely surrounds the table. You might feel a bit confined by the ring you have to lie in while the pictures are being taken. Spiral CT (also known as helical CT) is now used in many medical centers. This type of CT scan uses a faster machine that reduces the dose of radiation and yields more detailed pictures.
Magnetic resonance imaging (MRI) scan: Like CT scans, MRI scans provide detailed images of soft tissues in the body. But MRI scans use radio waves and strong magnets instead of x-rays. The energy from the radio waves is absorbed and then released in a pattern formed by the type of body tissue and by certain diseases. A computer translates the pattern into very detailed images of parts of the body. A contrast material called gadolinium is often injected into a vein before the scan to better see details.
MRI images are often used to determine the extent of a tumor's growth and spread. They are particularly useful in examining eye tumors. They are also helpful in finding cancer that has spread to the brain or spinal cord, as well as any spread of melanoma outside the eye orbit.
MRI scans take longer than CT scans — often up to an hour. You have to lie inside a narrow tube, which can be confining and may upset people with a fear of enclosed spaces. Newer, open MRI machines might help with this, but they might provide less detailed images and can't be used in all cases. The machine also makes buzzing and clicking noises that may be disturbing. Some people might need medicine to help them relax for the test.
This procedure may be done with either sedation and local anesthesia (numbing medicine) or while a person is under general anesthesia (in a deep sleep). A thin, hollow needle is passed into the eye, and cells from the tumor are sucked up into a small syringe. The sample is sent to a lab, where a doctor called a pathologist looks at the cells under a microscope.
A biopsy is needed to confirm the diagnosis of most cancers, but it is not often used for eye melanomas. The main reason for this is that it is hard to get a sample of the tumor without damaging the eye. Also, the biopsy could possibly spread the tumor outside the eye. For these reasons, and because almost all cases can be accurately diagnosed by the eye exam and imaging tests, most people with melanoma of the eye are treated without having a biopsy first. This may change in the future. New technology may make biopsy safer in situations where the diagnosis is uncertain.
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 functioning. Abnormal test results can sometimes be a sign that the cancer has spread to the liver.
Diagnosing intraocular lymphoma
Signs and symptoms of intraocular lymphoma
The possible signs and symptoms of eye lymphomas include:
- Blurred vision or loss of vision
- Seeing floaters (spots or squiggles drifting in the field of vision)
- Redness or swelling in the eye
- Sensitivity to light
- Eye pain (uncommon)
Intraocular lymphoma most often affects both eyes, but it can cause more symptoms in one eye than in the other.
Most often, these symptoms are caused by other, less serious conditions. For example, floaters may occur as 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.
Many of the exams and tests mentioned below are described in more detail in the section on diagnosing intraocular melanomas.
The doctor will ask about any symptoms you are having and may check your vision and eye movements. During the eye exam, the doctor will use an ophthalmoscope (an instrument with a light and a small magnifying lens) to get a good look inside the eye. If lymphoma is present, the doctor may see that the vitreous (the jelly-like substance that fills most of the inside of the eye) is cloudy.
Ultrasound: Ultrasound is usually done to assess the nature of the mass (tumor), especially if the back of the eye can't be seen during the eye exam.
MRI scan: MRI is often done not only to see the eye better, but also to look for lymphoma in the brain or meninges (the thin layers of tissue that cover the brain and spinal cord), which are common sites of spread of this cancer.
CT scan: CT scans are used less often than MRI scans for eye lymphoma because they do not provide as much detail.
Positron emission tomography (PET) scan: For a PET scan, a radioactive substance (usually a type of sugar related to glucose, known as FDG) is injected into the blood. The amount of radioactivity used is very low. Because cancer cells in the body are growing quickly, they absorb larger amounts of the sugar than most other cells. A special camera can then create a picture of areas of radioactivity in the body. The picture is not finely detailed like a CT or MRI scan, but it can provide helpful information about whether abnormal areas seen on other tests (such as MRIs) are likely to be cancer.
A PET scan can help give the doctor a better idea of whether the cancer has spread to lymph nodes or other parts of the body. A PET scan can also be useful if your doctor thinks the cancer may have spread but doesn't know where.
Often, a machine is used that can do both a PET and CT scan at the same time (PET/CT scan). This lets the doctor compare areas of higher radioactivity on the PET scan with the more detailed appearance of that area on the CT.
Symptoms and the results of exams and tests might suggest you have intraocular lymphoma, but a biopsy is usually needed to confirm the diagnosis. To biopsy the eye, an ophthalmologist most often does a procedure called a vitrectomy. You may be sedated and get local anesthesia (numbing medicine) or you may get general anesthesia (which puts you in a deep sleep). The doctor takes a sample of the vitreous gel from inside the eye by inserting very small instruments into the eye, cutting the vitreous, and then sucking some of it out. The cells in the biopsy sample are then sent to a lab to be looked at under a microscope and tested by other special techniques. For more information on the lab tests done on suspected lymphoma specimens, see our document, Non-Hodgkin Lymphoma.
Lumbar puncture (spinal tap)
This procedure is used to look for lymphoma cells in the fluid that surrounds the brain and spinal cord (called cerebrospinal fluid or CSF). It is done in cases of known or suspected eye lymphomas because these cancers often affect the brain or spinal cord.
For this test, you lie on your side on a bed or exam table with your knees up near your chest. The doctor first numbs an area in the lower part of the back near the spine. A small, hollow needle is then placed between the bones of the spine to withdraw some of the fluid.
The fluid is then examined under a microscope to look for lymphoma cells. Other tests may be done on the fluid as well.
Last Medical Review: 06/27/2011
Last Revised: 01/18/2013