Tunnel vision

Normal vision. Courtesy NIH National Eye Institute

The same view with tunnel vision from retinitis pigmentosa.

Tunnel vision is a visual problem or symptom of another problem which produces loss of peripheral vision, as illustrated.

Tunnel vision can be caused by:

• retinitis pigmentosa, a disease of the eye.
• sustained (1 second or more) high accelerations, resulting in peripheral light loss.[1]. Can occur in fighter pilots during combat or testing situations. More severe symptoms can include loss of consciousness.
• hallucinogenic drugs.
• glaucoma, a disease of the eye.
• altitude sickness, hypoxia in passenger aircraft[2]
• exposure to oxygen at a partial pressure above 1.5-2 atmospheres, producing central nervous system oxygen toxicity, notably while diving.[3] 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[4].

The expression "tunnel vision" may also be used as a metaphor for narrowmindedness. When combined with piloting an aircraft, driving, crossing roads or operating heavy machinery, the consequences have been known to be fatal.