Diagnosis is the process of finding the cause of a health problem. The process of diagnosis may seem long and frustrating, but it is important for the doctor to rule out other reasons for a health problem before making a cancer diagnosis. Diagnostic tests for eye cancer are usually done when:
Many of the same tests used to initially diagnose cancer are used to determine 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. Tests may include the following.
The medical history is a record of present symptoms, risk factors and all the medical events and problems a person has had in the past. The medical history of a person’s family may also help the doctor to diagnose eye cancer.
In taking a medical history, the doctor will ask questions about:
An eye (ophthalmic) examination allows the doctor to check vision, assess the health of the eyes and look for any signs of eye cancer. An eye examination is done by an eye specialist (ophthalmologist). They examine the eyes by doing a series of tests with different instruments, such as:
Drops may be put in the eyes to enlarge (dilate) the pupil, which helps the doctor see structures inside the eye better. During an eye examination, the doctor may:
Ultrasound uses high-frequency sound waves to make images of structures in the body. An ultrasound of the eye and orbit is used to:
Drops are sometimes used to numb the eye before the ultrasound is done, or ultrasound can be done without eye drops. The ultrasound probe is gently placed over closed eyelids or on the surface of the eye.
Two types of ultrasound may be used to examine the eye (ophthalmic ultrasound) – ultrasound A and B. Both are used to determine the size, features and extent of an eye melanoma. They are also used to find out if the eye tumour is a metastasis from another part of the body.
An ultrasound of the liver may also be done if the doctor suspects that the eye cancer (such as an eye melanoma) has spread to the liver.
Fluorescein angiography is a procedure used to x-ray blood vessels inside the eye. A special dye called fluorescein is used to make blood vessels in the eye visible on the x-ray. Drops are first given to enlarge (dilate) the pupil of the eye. Then the dye is injected into the arm and travels to the blood vessels in the eye. A series of pictures are then taken to:
A similar test, indocyanine green angiography (ICG), uses a special green dye to look at the blood vessels in the retina. This procedure is useful for detecting disease in the choroid of the eye.
During a biopsy, tissues or cells are removed from the body so they can be tested in a laboratory. The pathology report from the laboratory will confirm whether or not cancer cells are present in the sample.
Unlike most other cancers, which need a biopsy to confirm the diagnosis, cancers within the eye can usually be diagnosed by an eye examination and imaging. A biopsy is not needed in many cases and doctors tend to avoid taking a biopsy from the eye itself. It can be difficult to get a sample of the tumour without damaging the eye and possibly spreading the tumour. A biopsy can be taken from accessory (adnexal) structures outside the eye, such as the eyelid.
However, intraocular lymphoma cannot be diagnosed with an eye examination and imaging, so a biopsy is usually required.
The biopsies that may be used for eye cancer are:
A CT scan uses special x-ray equipment to make 3-dimensional and cross-sectional images of organs, tissues, bones and blood vessels inside the body. A computer turns the images into detailed pictures. It is used to:
MRI uses powerful magnetic forces and radio-frequency waves to make cross-sectional images of organs, tissues, bones and blood vessels. A computer turns the images into 3-dimensional pictures. It is used to:
Blood chemistry tests measure certain chemicals in the blood. They show how well certain organs are functioning and can also be used to detect abnormalities. Some blood chemistry tests are used to help stage eye cancer.
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 an eye cancer (such as melanoma of the eye) has spread to the lung.
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