Cancer that forms in tissues of and around the eye. Some of the cancers that may affect the eye include melanoma (a rare cancer that begins in cells that make the pigment melanin in the eye), carcinoma (cancer that begins in tissues that cover structures in the eye), lymphoma (cancer that begins in immune system cells), and retinoblastoma (cancer that begins in the retina and usually occurs in children younger than 5 years).
Intraocular melanoma is a disease in which malignant (cancer) cells form in the tissues of the eye.
Intraocular melanoma begins in the middle of 3 layers of the wall of the eye. The outer layer includes the white sclera (the "white of the eye") and the clear cornea at the front of the eye. The inner layer has a lining of nerve tissue, called the retina, which senses light and sends images along the optic nerve to the brain.
The middle layer, where intraocular melanoma forms, is called the uvea or uveal tract, and has 3 main parts:
The iris is the colored area at the front of the eye (the "eye color"). It can be seen through the clear cornea. The pupil is in the center of the iris and it changes size to let more or less light into the eye.
- Ciliary body
The ciliary body is a ring of tissue with muscle fibers that change the size of the pupil and the shape of the lens. It is found behind the iris. Changes in the shape of the lens help the eye focus. The ciliary body also makes the clear fluid that fills the space between the cornea and the iris.
The choroid is the layer of blood vessels that bring oxygen and nutrients to the eye. Most intraocular melanomas begin in the choroid.
Intraocular melanoma is a rare cancer, but it is the most common eye cancer in adults.
Age and sun exposure may increase the risk of developing intraocular melanoma.
Anything that increases your risk of getting a disease is called a risk factor. Having a risk factor does not mean that you will get cancer; not having risk factors doesn’t mean that you will not get cancer. People who think they may be at risk should discuss this with their doctor. Risk factors for intraocular melanoma include the following:
- Being exposed to natural sunlight or artificial sunlight (such as from tanning beds) over long periods of time.
- Having a fair complexion, which includes the following:
- Fair skin that freckles and burns easily, does not tan, or tans poorly.
- Blue or green or other light-colored eyes.
- Older age.
- Being white.
Possible signs of intraocular melanoma include a dark spot on the iris or blurred vision.
Intraocular melanoma may not cause any early symptoms. It is sometimes found during a routine eye exam when the doctor dilates the pupil and looks into the eye. The following symptoms may be caused by intraocular melanoma or by other conditions. A doctor should be consulted if any of these problems occur:
- A dark spot on the iris.
- Blurred vision.
- A change in the shape of the pupil.
- A change in vision.
Glaucoma may develop if the tumor causes the retina to separate from the eye. If this happens, there may be no symptoms, or symptoms may include the following:
- Eye pain.
- Blurred vision.
- Eye redness.
Tests that examine the eye are used to help detect (find) and diagnose intraocular melanoma.
The following tests and procedures may be used:
- Eye exam with dilated pupil: An examination of the eye in which the pupil is dilated (enlarged) with medicated eyedrops to allow the doctor to look through the lens and pupil to the retina. The inside of the eye, including the retina and the optic nerve, is examined using an instrument that produces a narrow beam of light. This is sometimes called a slit-lamp exam. The doctor may take pictures over time to keep track of changes in the size of the tumor and how fast it is growing.
- Indirect ophthalmoscopy: An examination of the inside of the back of the eye using a small magnifying lens and a light.
- Ultrasound exam of the eye: A procedure in which high-energy sound waves (ultrasound) are bounced off the internal tissues of the eye to make echoes. Eye drops are used to numb the eye and a small probe that sends and receives sound waves is placed gently on the surface of the eye. The echoes make a picture of the inside of the eye. The picture, called a sonogram, shows on the screen of the ultrasound monitor.
- Transillumination of the globe and iris: An examination of the iris, cornea, lens, and ciliary body with a light placed on either the upper or lower lid.
- Fluorescein angiography: A procedure to look at blood vessels and the flow of blood inside the eye. An orange fluorescent dye (fluorescein) is injected into a blood vessel in the arm. As the dye travels through blood vessels of the eye, a special camera takes pictures of the retina and choroid to detect any blockage or leakage.
Retinoblastoma is a disease in which malignant (cancer) cells form in the tissues of the retina.
The retina is the nerve tissue that lines the inside of the back of the eye. The retina senses light and sends images to the brain by way of the optic nerve.
Although retinoblastoma may occur at any age, it usually occurs in children younger than 5 years, most often younger than 2 years. The tumor may be in one eye or in both eyes. Retinoblastoma rarely spreads from the eye to nearby tissue or other parts of the body.
Retinoblastoma is sometimes caused by a gene mutation passed from the parent to the child.
Retinoblastoma is sometimes inherited (passed from the parent to the child). Retinoblastoma that is caused by an inherited gene mutation is called hereditary retinoblastoma. It usually occurs at a younger age than retinoblastoma that is not inherited. Retinoblastoma that occurs in only one eye is usually not inherited. Retinoblastoma that occurs in both eyes is always inherited.
When hereditary retinoblastoma first occurs in only one eye, there is a chance it will develop later in the other eye. After diagnosis of retinoblastoma in one eye, regular follow-up exams of the healthy eye should be done every 2 to 4 months for at least 28 months. After treatment for retinoblastoma is finished, it is important that follow-up exams continue until the child is 5 years of age.
Treatment for both types of retinoblastoma should include genetic counseling (a discussion with a trained professional about inherited diseases). Brothers and sisters of a child who has retinoblastoma should also have regular exams by an ophthalmologist (a doctor with special training in diseases of the eye) and genetic counseling about whether they should be tested for the gene that causes retinoblastoma and the risk of the child's brothers or sisters developing retinoblastoma. The child's brothers and sisters also should have regular eye exams by an ophthalmologist until age 5 years.
A child who has hereditary retinoblastoma is at risk for developing trilateral retinoblastoma and other cancers.
A child who has hereditary retinoblastoma is at risk for developing pineal tumors in the brain. This is called trilateral retinoblastoma and usually occurs more than 20 months after retinoblastoma is diagnosed. Regular screening using MRI (magnetic resonance imaging) every 6 months for 5 years may be recommended for a child with hereditary retinoblastoma or with retinoblastoma in one eye and a family history of the disease. CT scans (computerized tomography) should not be used for routine screening to avoid exposing the child to ionizing radiation. Hereditary retinoblastoma also increases the child's risk of developing other types of cancer such as bone or soft tissue sarcoma or melanoma in later years. Regular follow-up exams are important.
Possible signs of retinoblastoma include "white pupil" and eye pain or redness.
These and other symptoms may be caused by retinoblastoma. Other conditions may cause the same symptoms. A doctor should be consulted if any of the following problems occur:
- Pupil of the eye appears white instead of red when light shines into it. This may be seen in flash photographs of the child.
- Eyes appear to be looking in different directions.
- Pain or redness in the eye.
Tests that examine the retina are used to detect (find) and diagnose retinoblastoma.
The following tests and procedures may be used:
- Physical exam and history: An exam of the body to check general signs of health, including checking for signs of disease, such as lumps or anything else that seems unusual. A history of the patient's health habits and past illnesses and treatments will also be taken. The doctor will ask if there is a family history of retinoblastoma.
- Eye exam with dilated pupil: An exam of the eye in which the pupil is dilated (opened wider) with medicated eyedrops to allow the doctor to look through the lens and pupil to the retina. The inside of the eye, including the retina and the optic nerve, is examined with a light. Depending on the age of the child, this exam may be done under anesthesia.
- Ultrasound exam: A procedure in which high-energy sound waves (ultrasound) are bounced off internal tissues or organs and make echoes. The echoes form a picture of body tissues called a sonogram.
- CT scan (CAT scan): A procedure that makes a series of detailed pictures of areas inside the body, such as the eye, taken from different angles. The pictures are made by a computer linked to an x-ray machine. A dye may be injected into a vein or swallowed to help the organs or tissues show up more clearly. This procedure is also called computed tomography, computerized tomography, or computerized axial tomography.
- MRI (magnetic resonance imaging): A procedure that uses a magnet, radio waves, and a computer to make a series of detailed pictures of areas inside the body, such as the eye. This procedure is also called nuclear magnetic resonance imaging (NMRI).
Retinoblastoma is usually diagnosed without a biopsy (removal of cells or tissues so they can be viewed under a microscope to check for signs of cancer).
Certain factors affect prognosis (chance of recovery) and treatment options.
The prognosis (chance of recovery) and treatment options depend on the following:
- The stage of the cancer.
- The age of the patient.
- How likely it is that vision can be saved in one or both eyes.
- The size and number of tumors.
- Whether trilateral retinoblastoma occurs.