When a person is diagnosed with a brain tumor, several factors must be taken into consideration. One is trying to ensure that the portion of the brain that deciphers visual impulses is not damaged. To diagnose a brain tumor, a doctor will use an imaging test such as a CT scan and an MRI, along with a biopsy of the material from the tumor itself if such a biopsy can be safely obtained. In some cases, a determination as to whether or not a tumor is cancerous is made after it is removed.
A brain tumor is a collection of cells that have grown at an abnormal pace. In some cases, these tumors originate in the brain itself and are called primary brain tumors. Tumors that originated from some other part of the body are called metastatic brain tumors. A brain tumor filled with cancerous cells is called malignant, while non-cancerous tumors are called benign. Many of the preliminary symptoms associated with the creation of a tumor are the same regardless of whether the tumor is malignant or benign. It is when a malignant tumor starts to spread cancerous cells to other parts of the brain and the body that the differences begin to appear.
The effect of a brain tumor, malignant or benign, on vision is normally a slowly developing set of symptoms. The person may experience recurring bouts of double vision or blurred vision, and as the symptoms get more advanced, these vision problems may be accompanied by a painful headache. This change in vision due to a brain tumor is due to the pressure that the growing tumor is putting on the various parts of the brain. If a tumor is developing away from the vision center of the brain, then there may be no vision symptoms at all. Tumors that develop near the vision center of the brain can create very uncomfortable vision symptoms.
Loss of Peripheral Vision
One of the more potentially dangerous vision symptoms of a brain tumor is the loss of peripheral vision, which is located on the very outer edges of the vision field, and it is responsible for a person's ability to see danger coming from one side or the other. In some cases, a brain tumor may be growing in an area that causes that field of vision to get smaller, and this causes the eventual loss of peripheral vision.
The most common method of treating a brain tumor is to have it surgically removed. Once the tumor is removed, it is possible to regain much of the vision that was lost. However, in some cases, factors such as peripheral vision may never completely return. Doctors will often recommend ongoing physical, occupational and cognitive therapy to help survivors of brain tumors regain as much of their vision as possible, and learn to adapt to living without the vision they have permanently lost.
The Mayo Clinic suggests that the damage done to the nerves associated with vision due to a brain tumor can be permanent. If a tumor resides in the visual cortex, the portion of the brain that processes visual stimulus, then the process of removing that tumor may leave permanent vision problems. The tumor itself could also create permanent vision problems simply by creating pressure in that part of the brain and killing brain cells.