Tunnel vision



In medical terms, tunnel vision is the loss of peripheral vision with retention of central vision, resulting in a constricted circular tunnel-like field of vision.

Tunnel vision can be caused by:
 * Alcohol consumption causes tunnel vision . In addition, the vision becomes blurred or double since eye muscles lose their precision causing them to be unable to focus on the same object.
 * Retinitis pigmentosa, a disease of the eye.
 * Group B Rally driving (1985, 1986)
 * Sustained (1 second or more) high accelerations . Typically, flying an airplane with a centripetal acceleration of up to or over 39 m/s2 (4gs) with the head towards the center of curvature, common in aerobatic or fighter pilots. In these cases tunnel vision and brownout may proceed to or g-force induced Loss Of Consciousness (g-LOC).
 * Hallucinogenic drugs.
 * Glaucoma, a disease of the eye.
 * Extreme fear or distress, most often in the context of a panic attack.
 * During an intense physical fight.
 * Altitude sickness, hypoxia in passenger aircraft
 * Exposure to oxygen at a partial pressure above 1.5-2 atmospheres, producing central nervous system oxygen toxicity, notably while diving. Other symptoms can include dizziness, nausea, blindness, fatigue, anxiety, confusion and lack of coordination.
 * Other loss of blood to the brain.
 * Prolonged exposure to air contaminated with heated hydraulic fluids and oils, as can sometimes happen in passenger aircraft.
 * Pituitary stalk mass (i.e. tumor) compressing the optic chiasm
 * Severe cataracts, causing a removal of most of the field of vision
 * During the aura phase of a migraine
 * Intense anger, due to the body being rapidly flooded with adrenaline and oxygen
 * High doses of dextromethorphan

When combined with piloting an aircraft, driving, crossing roads or operating heavy machinery, the consequences have been known to be fatal.