eye cancer diagnosed?

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 quite 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 cause some 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.


Eye exam


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 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.

• 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, often providing a more detailed view of the inside of the eye than the direct ophthalmoscope.
• Gonioscopy: the cornea is numbed and then a specially mirrored lens (gonioscopy lens) is placed on it. This allows the doctor to see the deep structures in the angle of the front of the eye near the iris. This can provide information on tumor extension into hidden areas of the eye.

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 will a biopsy 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 cancer might be present, more involved tests will likely be done. These might include imaging tests or other procedures.


Imaging tests


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, and 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 sound waves to take pictures of parts of the body. For this test, 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 silent sound waves at high 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.


Angiography: This is another technique used by ophthalmologists to help diagnose melanoma of the eye. A fluorescent dye is injected into the bloodstream through a vein in the arm. Pictures of the back of the eye are then taken with light that causes the dye to fluoresce (glow). This allows the doctor to 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. This technique is also called fluoroscein angiography. When a special green dye is used to look at the blood vessels, it is known as indocyanine green angiography (ICG).


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 procedure that produces detailed cross-sectional images of your body. Instead of taking one picture, like a conventional x-ray, a CT scanner takes many pictures as it rotates around you. A computer then combines these pictures into 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. The injection can 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 ever had a reaction to any contrast material used for x-rays.


You need to lie still on a table while the scan is being done. During the test, the table moves 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.


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 scans may be a little more uncomfortable than CT scans. They can take up to an hour. You may be placed inside a large cylindrical tube, which is confining and can upset people with a fear of enclosed spaces. Special, "open" MRI machines can help with this if needed. The MRI machine makes buzzing and clicking noises that you may find disturbing. Some places will provide earplugs to help block this out.


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 the melanoma outside the eye orbit.


Biopsy


In this procedure, a small, 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. This may change in the future. New technology may make biopsy safer in situations where the diagnosis is uncertain.


Blood tests


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.