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You may only think of tears as those salty drops that fall from your eyes when you cry. Actually, your tears clean your eyes every time you blink. Tears also keep your eyes moist, which is important for your vision.

Tear glands produce tears, and tear ducts carry the tears from the glands to the surface of your eye. Problems with the tear system can include too many tears, too few tears, or problems with the tear ducts. Treatment of the problem depends on the cause.

Tumors are abnormal growths in your body. They can be either benign or malignant. Benign tumors aren't cancer. Malignant ones are. Benign tumors grow only in one place. They cannot spread or invade other parts of your body. Even so, they can be dangerous if they press on vital organs, such as your brain.

Tumors are made up of extra cells. Normally, cells grow and divide to form new cells as your body needs them. When cells grow old, they die, and new cells take their place. Sometimes, this process goes wrong. New cells form when your body does not need them, and old cells do not die when they should. These extra cells can divide without stopping and may form tumor.

Treatment often involves surgery. Benign tumors usually don't grow back.

NIH: National Cancer Institute

Cancer of the eye is uncommon. It can affect the outer parts of the eye, such as the eyelid, which are made up of muscles, skin and nerves. If the cancer starts inside the eyeball it's called intraocular cancer. The most common intraocular cancers in adults are melanoma and lymphoma. The most common eye cancer in children is retinoblastoma, which starts in the cells of the retina. Cancer can also spread to the eye from other parts of the body.

Treatment for eye cancer varies by the type and by how advanced it is. It may include surgery, radiation therapy, freezing or heat therapy, or laser therapy.