Eye Cancer Facts

Eye cancer, or ocular cancer, refers to a tumor that affects any part of the eye, including the eyeball, the eyelid, the retina, the opening in the skull where the eye is contained (orbit) or the skin immediately surrounding the eye. There are several types of eye cancer that can be classified in a few ways. They can be separated according to where they begin---some begin in the eye area while others spread to the eye from other body parts. They can also be classified by the age group they affect---some rare ocular cancers are particular to children, while others can occur at any age. The most common division, however, is made between those cancers that affect the inside of the eye, called intraocular, and those that affect the tissues and structures surrounding the eyeball, called extraocular.

Primary Intraocular Cancers

• Intraocular cancers can be subdivided according to where they start. Primary intraocular cancers start within the eyeball. The most common varieties in adults are melanoma and primary intraocular lymphoma. In children, the most common is retinoblastoma, which begins in cells in the retina. Usually, intraocular cancers have no symptoms, and they are detected at regular eye exams, which is one reason you should visit your optometrist at least every other year even if you have no vision problems. Some ocular cancers may cause symptoms such as spotty vision or a crusty bump on the lid, but these symptoms are more commonly caused by eye problems other than cancer. Intraocular tumors are sometimes treated by excision (surgically removing the tumor) or, depending on the tumor's size, they may be treated with enucleation (removing the entire eye). This is often combined with radiotherapy.

Intraocular Melanoma (Melanoma of the Eye)

• While intraocular melanoma is the most common intraocular cancer that develops in adult eyes, it is still rare. Far more common is melanoma of the skin. Melanomas in the eyeball almost always develop in the uveal layer, which is the pigmented layer that lies between the corneosclera (outermost layer) and the retina (innermost layer). Intraocular melanoma may also start in the iris. These melanomas are easily detectable and generally come with a good prognosis. Melanomas of the eye can be classified by the type of cell that forms them. Spindle cell melanomas are made from long, thin cells. Epithelioid melanomas (also called non-spindle cell melanomas) are made from rounded cells or from a mixture of the two cell types. Most tumors are composed of both cell types, but those with all or mostly epithelioid cells are tougher to treat and have a higher likelihood of spreading to other areas of the body. Your doctor will always be able to tell you what type of cells dominate your tumor. While the cause of intraocular melanomas is unknown, some risk factors include light-colored eyes, oddly shaped or notably large moles, and exposure to UV rays. For these reasons, it is important to wear protective sunglasses and get any unusual moles checked by a doctor. Intraocular melanoma can be treated with laser therapy, which uses a laser to kill cancer cells, or radiotherapy, which uses radiation to kill cancer cells.

Primary Intraocular Lymphoma (Lymphoma of the Eye)

• Lymphoma begins in lymphocytes, which are cells found in the immune system. Lymphoma usually forms in lymph nodes, but it may also occur in internal organs or, very rarely, in the eye. There are two major classifications of lymphoma: Hodgkin's disease and non-Hodgkin's lymphoma. Primary intraocular lymphoma is always a non-Hodgkin's lymphoma. Most people with primary intraocular lymphoma have immune systems that have been seriously weakened. People with AIDS, those who have taken drugs to subdue their immune systems due to organ transplantation and elderly people face a much higher risk of developing this type of cancer than healthy people. Primary intraocular lymphoma may be treated with chemotherapy, which uses medicine to destroy cancer cells.

Intraocular Cancers in Children

• There are two types of ocular cancers that develop in children. The more common of these rare conditions is retinoblastoma, a condition passed along genetically that almost exclusively affects children under five. Children who squint and/or have a strange-looking pupil may be displaying symptoms of retinoblastoma. Chemotherapy can be used to treat this type of cancer. The other, even more rare, eye cancer that affects children is called medulloepithelioma. This cancer usually doesn't spread, so it can be dealt with by excision or enucleation.

Secondary Intraocular Cancers

• If the cancer spreads to the eyeball from another part of the body, this is called secondary intraocular cancer. More common than primary intraocular cancers, these aren't considered true ocular cancers. In women, breast cancer is the most usual culprit, while in men it is lung cancer.

Extraocular Cancers

• Cancers that develop in the eye's orbit, accessory muscles and surrounding skin develop from nerve, muscle and skin tissues. Melanoma of the conjunctiva (a transparent tissue that covers the eye's outer surface) and eyelid are both possibilities, but they are exceedingly rare. Extraocular cancers are treated as that type of cancer would be treated in any other body part. For example, basal cell skin cancer may affect the eyelid, but it would be treated as any other skin cancer. In rare cases, the muscles that move the eye may be affected by rhabdomyosarcoma. This is treated simply as muscle cancer.