Cancers Affecting the Retina
Cancers affecting the retina generally begin in the choroid, a dense layer of blood vessels that supplies the retina. The choroid is sandwiched between the retina and the sclera (the outer white part of the eye). Because the retina depends on the choroid for its blood supply and support, damage to the choroid by a cancer is likely to affect vision.
Choroidal Melanoma: Choroidal melanoma is a cancer that originates in the pigment-producing cells (melanocytes) of the choroid. Choroidal melanoma is the most common cancer originating in the eye. It is most common in people with fair complexions and blue eyes. In its early stages, the cancer usually does not interfere with vision. Later, it may cause blurred vision or complete loss of vision due to retinal detachment. Metastases to other parts of the body may occur.
Early diagnosis is important, because the likelihood of curing choroid melanoma is related to the size of the tumor. Diagnosis is made using an ophthalmoscope, ultrasound scanning, and serial photographs.
If the melanoma is small, treatment with a laser, radiation, or an implant of radioactive materials may preserve vision and save the eye. If the cancer is large, the eye must be removed. If a large cancer is not removed, it can spread directly into the eye socket (orbit) or through the bloodstream (metastasize) to other organs, causing death.
Choroidal Metastases: Choroidal metastases are cancers that have spread to the eye from other parts of the body. Because of its excellent blood supply, the choroid is often a place to which cancers from other parts of the body may spread. In women, breast cancer is the most common cause. In men, cancers of the lung or prostate are the most common causes.
Often, these cancers produce no symptoms and may be discovered during a routine eye examination. In those with symptoms, initial symptoms are decreasing vision and flashes of light. Retinal detachment and severe vision loss may occur.
The diagnosis is sometimes made during a routine eye examination with an ophthalmoscope. Diagnosis is aided by ultrasound scanning. Confirmation of the diagnosis may involve using a fine needle to remove a sample of tissue for examination under a microscope (biopsy). Treatment is usually with chemotherapy and radiation therapy.
| 
