Also called: Carcinoma, Malignancy, Neoplasms, Tumor
Cancer begins in your cells, which are the building blocks of your body. Normally, your body forms new cells as you need them, replacing old cells that die. Sometimes this process goes wrong. New cells grow even when you don’t need them, and old cells don’t die when they should. These extra cells can form a mass called a tumor. Tumors can be benign or malignant. Benign tumors aren’t cancer while malignant ones are. Cells from malignant tumors can invade nearby tissues. They can also break away and spread to other parts of the body.
Cancer is not just one disease but many diseases. There are more than 100 different types of cancer. Most cancers are named for where they start. For example, lung cancer starts in the lung, and breast cancer starts in the breast. The spread of cancer from one part of the body to another is called metastasis. Symptoms and treatment depend on the cancer type and how advanced it is. Most treatment plans may include surgery, radiation and/or chemotherapy. Some may involve hormone therapy, immunotherapy or other types of biologic therapy, or stem cell transplantation.
NIH: National Cancer Institute
The optic nerve is a bundle of more than 1 million nerve fibers that carry visual messages. You have one connecting the back of each eye (your retina) to your brain. Damage to an optic nerve can cause vision loss. The type of vision loss and how severe it is depends on where the damage occurs. It may affect one or both eyes.
There are many different types of optic nerve disorders, including:
Contact your health care provider if you are having vision problems. Tests for optic nerve disorders may include eye exams, ophthalmoscopy (an examination of the back of your eye), and imaging tests. Treatment depends on which disorder that you have. With some optic nerve disorders, you may get your vision back. With others, there is no treatment, or treatment may only prevent further vision loss.