Eye cancers are characterized by an overgrowth of abnormal cells in the eye. The eye is an unusual site for cancer to develop. Its structure and specialized tissues create special challenges in both treating the cancer and preserving vision.

The eye is composed of the globe (eyeball), orbit (the bony canal containing the eyeball) and adnexal (accessory) structures, such as the eyelids and tear glands. This guide focuses on intraocular cancers (cancers of the eyeball) because they have a unique effect on the eye.

Intraocular cancers can be primary eye cancers, which first appear inside the eyeball, or they can be secondary eye cancers, which spread (metastasize) to the eyeball from other locations in the body. Types of primary eye cancer include:

• Intraocular melanoma. Also called uveal melanoma, intraocular melanoma is the most common primary eye cancer in adults.
  
  
• Primary intraocular lymphoma.  Lymphoma is a form of cancer that may occur in the eye but typically begins in the lymph nodes (bean-sized groups of immune system cells that help ward off infections and cancers). It mainly affects older adults and people with weakened immune systems.
  
  
• Retinoblastoma. Retinoblastoma is a rare cancer that begins in the retina and primarily affects young children.
  
  
• Embryonal medulloepithelioma. Medulloepithelioma is an extremely rare  tumor in the eye that affects young children. Other epitheliomas are brain tumors.

Different types of cancer have different risk factors. For instance, people with blue eyes are more likely to develop intraocular melanoma than those with brown eyes.

All forms of eye cancer are diagnosed after a complete eye examination, which may include a variety of screening tests to determine if cancer is present and has spread to distant sites. Many types of cancer can be diagnosed with a biopsy, but this is extremely difficult to perform on the eye.

When treating eye cancers, physicians weigh such factors as the stage of the cancer and the ability to save the eye or preserve vision. Eye cancer may be treated with numerous therapies, including radiation therapy and chemotherapy  and surgery, which may involve removal of the eye (enucleation). Researchers are investigating new methods of treating eye cancers.