Tunnel vision is a medical condition that results in a loss of peripheral vision. As a result, the patient can only see objects from within a circular field. This condition has many possible causes, including brain problems, some eye diseases, hallucinogenic drugs, and certain extreme activities.
Blood loss in parts of the brain can lead to tunnel vision, just like a tumor pressing against the optic fibers ever. A person who is exposed to air that has been contaminated by oils and hydraulic fluids, such as can occur on an airplane, can also develop this condition. Getting sick while on a plane can cause temporary vision problems.
Certain eye diseases can also lead to tunnel vision. Retinitis pigmentosa, an inherited condition that can eventually lead to blindness, may be one cause. This disorder usually begins by showing itself as night blindness, which then leads to a loss of peripheral vision and eventually blindness. However, not all people with the disorder go blind.
Glaucoma, a disease that affects the optic nerve, can also cause tunnel vision. The pressure exerted on the optic nerve causes the eye to lose retinal ganglion cells, which can eventually render the patient blind. For some patients, peripheral vision loss may be experienced prior to blindness.
Hallucinogenic drug use can also cause brain and nerve damage, which can result in permanent or temporary tunnel vision. Extreme stress, such as that experienced during a panic attack, is another possible cause. Specific sports and activities can also cause a temporary loss of peripheral vision. Fighter pilots and aerobats, for example, may experience this problem during sustained high acceleration of one or more seconds. In this case, the person may also lose consciousness.
Exposure to oxygen at pressures greater than 1.5 to two atmospheres can be toxic to the central nervous system. This occurs most often when diving. In addition to tunnel vision, this oxygen pressure can cause fatigue, dizziness, blindness, nausea, confusion, anxiety, and lack of coordination. When peripheral vision loss strikes a person involved in an activity such as driving or piloting an aircraft, it can lead to death, because the person cannot see properly.