Cancer affects the eyes no differently than it does the rest of the body. It can start in an eye or spread from another part of the body to the eye. When healthy cells grow or multiply uncontrollably, they form a mass of cells or tumor. Cancerous tumors that get bigger and spread to other parts of the body are considered malignant. However, a tumor can grow and not spread; This is called a benign tumor.
Cancer that originates inside the eyeball is considered an intraocular malignancy. If the cancer first forms in the eye, it is a primary intraocular cancer. Secondary intraocular cancer starts in another part of the body and spreads to the eye.
Symptoms of Ocular Cancer
Some people do not experience any symptoms, however, this varies greatly on the type and location of the tumor. Blurry or distorted vision, a spot in the vision, or a sudden increase in floaters can all be symptoms of intraocular cancer. There are plenty of other non-cancerous causes of these same symptoms, which makes annual eye exams so important. Cancerous lesions on the eyelid or front of the eye can be seen while looking at a mirror. Intraocular cancer can only be detected through a dilated eye exam.
Cancers of the Eyelid
Skin cancer is the usual culprit for cancer on the eyelids. Basal cell carcinoma, squamous cell carcinoma, and melanoma are the most common forms of cancer to affect the eyelids. Some lesions look like a scabbed-over bump that never fully heals, while others look like a dark spot on the eyelid. If addressed early, these lesions are usually not dangerous or life-threatening. Wearing sunglasses to protect the sensitive skin around the eyes can help prevent skin cancer.
Cancers of the Conjunctiva
The conjunctiva is a thin, clear layer that covers the sclera (white part of the eye) and extends onto the inner eyelid. Melanoma and lymphoma tumors can occur on the conjunctiva. Although cancer on the front of the eye is rare, it can easily spread through the blood and lymph system to other organs. These lesions can appear dark, like a skin mole, or flesh-colored.
Intraocular Cancers
Melanoma typically occurs in the pigmentary cells of the uvea (middle layer of the eye), which is comprised of the iris, ciliary body, and choroid. The choroidal layer is most commonly affected by melanoma because the pigmentary cells are most similar to those in the skin where melanoma is usually associated. Iris melanoma is a slow growing dark spot on the iris, which is unlikely to spread to other parts of the body.
Both primary and secondary lymphoma can present inside the eye, which makes it very important for those with already diagnosed cancer to have regular dilated eye exams. Breast and lung cancers are most likely to spread, or metastasize, to the eye.
Retinoblastoma is a rare childhood cancer that usually starts in the retina of one eye and is diagnosed by 2 years of age. The goal of treatment is to preserve vision and stop the cancer from spreading to other parts of the body.
Treating Ocular Cancer
Prompt diagnosis and treatment are the most important factors when it comes to cancer anywhere in the body. Medical and technological advancements are constantly evolving, which ultimately saves lives. Small cancerous lesions on the eyelid can be removed without complication, whereas intraocular melanoma may have a more severe “life or death” outcome. Radiation and surgery are the main types of treatment. Enucleation, or removal of the eye, is the worst visual outcome, but sometimes necessary for survival.
