Diagnosis of eye cancer

Diagnosis is the process of finding the cause of a health problem. The process of diagnosis may seem long and frustrating. It’s normal to worry, but try to remember that other health conditions can cause similar symptoms as eye cancer. It’s important for the healthcare team to rule out other reasons for a health problem before making a diagnosis of eye cancer. Diagnostic tests for eye cancer are usually done when:

• a routine eye exam suggests a problem with the eye (how most eye cancers are found)
• the symptoms of eye cancer are present

The following tests are usually used to rule out or diagnose eye cancer. Many of the same tests used to diagnose cancer are used to find out the stage (how far the cancer has progressed). Your doctor may also order other tests to check your general health and to help plan your treatment.

Your health history is a record of your symptoms, risk factors and all the medical events and problems you have had in the past. Your doctor will ask questions about your history of:

• symptoms that suggest eye cancer
• certain eye conditions (primary acquired melanosis or ocular melanocytosis)
• skin or eye moles
• HIV (human immunodeficiency virus) or AIDS (acquired immunodeficiency syndrome)
• spending time in the sun and indoor tanning
• welding

Your doctor may also ask about a family history of eye and other cancers.

A physical exam allows your doctor to look for any signs of eye cancer. During a physical exam, your doctor may:

• look at the surface of the eye
• feel your neck and abdomen for signs of swelling

Find out more about physical exams.

An eye exam is done by an eye specialist. An optometrist is the specialist you likely see for routine eye exams. If there is a problem with the eye, your doctor or optometrist may refer you to an ophthalmologist, a medical doctor who specializes in eye conditions. An eye exam is done to check:

• vision
• eye movement
• for abnormal areas on the surface of the eye and inside the eye

The eyes are examined with different instruments, including:

• ophthalmoscope – a lighted instrument with a magnifying lens that examines the back of the eye, including the retina and optic nerve
• slit lamp – a type of microscope that uses a strong beam of light to examine the inside of the eye
• gonioscope – a special lens put directly on the surface of the eye to examine the front of the eye
• transillumination – a special lighted instrument placed on the eyelid to examine the front of the eye
• optomap (retinal imaging) – a digital scanning system that makes pictures of most of the retina
• optical coherence tomography (OCT) – a type of imaging test that uses light waves to take cross-sectional pictures of the retina, choroid and sclera
• tonometry – a test that measures pressure inside the eye by applying an instrument to the cornea of the eye or applying a warm puff of air to the surface of the eye

Before an eye exam, the doctor may use eye drops to make the pupils larger (dilate the pupils). This helps the doctor to see the structures inside the eye better. Since these drops can cause changes to vision for a few hours, you shouldn’t drive after the appointment.

An ultrasound uses high-frequency sound waves to make images of parts of the body. It is used to:

• diagnose melanoma of the eye
• find the location and size of an eye tumour
• look for cancer that has spread to nearby parts of the body
• look for cancer that has spread to the liver
• plan radiation therapy
• check how well treatment is working

An eye ultrasound uses a small, wand-like instrument called an ultrasound probe. It is gently placed over closed eyelids or directly on the surface of the eye. Anesthetic eye drops are sometimes used to numb the eye before the ultrasound is done.

A high-resolution ultrasound biomicroscopy is sometimes used instead of a regular ultrasound. This technique gives a more detailed picture of the structures at the front of the eye.

An abdominal ultrasound uses a larger ultrasound probe on the abdomen. An abdominal ultrasound is sometimes done to look for cancer that has spread to the liver.

Learn more about ultrasounds.

An angiography is an x-ray used to take pictures of blood vessels. An orange or green dye is injected into the arm. The dye travels to blood vessels inside the eye. Drops are given to make the pupils larger (called dilating the pupils).

A CBC measures the number and quality of white blood cells, red blood cells and platelets. A CBC is done to check your general health.

Find out more about a complete blood count (CBC)..

Liver and kidney function tests measure certain chemicals in the blood. These tests can show how well the liver and kidney are working and help find something abnormal in these organs. An abnormal liver function test result may be a sign that eye cancer has spread to the liver.

Find out more about liver and kidney function tests.

During a biopsy, the doctor removes tissues or cells from the body so they can be tested in a lab. A report from the pathologist will confirm whether or not cancer cells are in the sample. A biopsy of the eye may remove part of a suspicious area (called an incisional biopsy) or all of a suspicious area (called an excisional biopsy).

Most types of cancer need a biopsy to confirm a cancer diagnosis. But some cancers in the eye can be diagnosed with only an eye exam or imaging test. Doctors try to avoid removing tissue from the eye because it can be hard to get a sample of the tumour without damaging the eye or spreading the cancer.

A biopsy is most often done:

• when a diagnosis can’t be made with other tests
• when the doctor recommends cytogenetic tests
• to remove a suspicious area surrounding the eye, such as the eyelid

There are special types of biopsies that are also used to help diagnose eye cancer or see where it may have spread.

Find out more about biopsies.

A fine needle aspiration (FNA) may be done to diagnose eye cancer, especially when the results from other tests aren’t clear. It uses a very thin needle to remove a small sample of cells from the abnormal area of the eye.

Learn more about an FNA.

A vitreous biopsy (also called a vitrectomy) is a procedure to help diagnose lymphoma of the eye. It uses very small instruments to remove some of the jelly-like fluid inside the eye (called vitreous humour) through several small cuts (incisions) in the eye.

A bone marrow aspiration and biopsy is a procedure that removes cells from the bone marrow so they can be looked at under a microscope. It is done if a person has been diagnosed with lymphoma of the eye. It is used to see if the lymphoma has spread to the bone marrow.

Learn more about a bone marrow aspiration and biopsy.

Genetic tests look for changes in genes, chromosomes or proteins that are sometimes found in people with cancer. The results of genetic tests can help doctors predict the prognosis and plan treatment. Genetic tests can be done on a sample of cells removed during a biopsy or on tissue removed with surgery.

Cytogenetics is the study of a cell’s chromosomes, including the number, size, shape and how they are arranged. Cytogenetic tests (chromosomal analysis) show changes to chromosomes. This helps doctors predict a prognosis in people with eye cancer. The results of cytogenetic tests also help doctors plan treatment and predict whether or not the cancer is likely to come back or spread.

Gene expression profiling lets doctors look at many genes at the same time to see which are turned on and which are turned off. Gene expression can help predict which eye cancers are most likely to spread.

A computed tomography (CT) scan uses special x-ray equipment to make 3-D and cross-sectional images of organs, tissues, bones and blood vessels inside the body. A computer turns the images into detailed pictures.

A CT scan is used to:

• find out the size of an eye tumour
• see if eye cancer has spread to nearby parts of the body
• look for cancer that has spread to distant areas of the body

A dye (contrast medium) may be given by mouth or injected into a vein (given intravenously) or both before the CT scan. The dye can help the doctor to see areas of the body better. Tell your doctor or the radiology staff if you have had an allergic reaction to dye in the past.

Find out more about CT scans.

Magnetic resonance imaging (MRI) uses powerful magnetic forces and radiofrequency waves to make cross-sectional images of organs, tissues, bones and blood vessels. A computer turns the images into 3-D pictures.

An MRI is used to:

• find out the size of an eye tumour
• see if eye cancer has spread to nearby parts of the body
• look for cancer that has spread to distant areas of the body, including the brain and spinal cord

A dye may be injected into a vein (given intravenously) before the MRI scan. The dye can help the doctor to see areas of the body better. Tell your doctor or the radiology staff if you have had an allergic reaction to dye in the past.

Find out more about MRIs.

An x-ray uses small doses of radiation to make an image of the body’s structures on film. A chest x-ray may be done to find out if eye cancer has spread to the lung.

Find out more about x-rays.

A positron emission tomography (PET) scan uses radioactive materials called radiopharmaceuticals to look for changes in the metabolic activity of body tissues. A computer analyzes the radioactive patterns and makes 3-D colour images of the area being scanned. A PET scan is sometimes used to look for eye cancer that has spread to distant areas of the body.

Find out more about PET scans.

A PET-CT scan combines a CT scan and a PET scan. It is sometimes used to look for eye cancer that has spread to lymph nodes or other areas of the body.

To make the decisions that are right for you, ask your healthcare team questions about a diagnosis.