Definition
A loss of vision in the center of the visual field, leaving only peripheral (side) vision functional. In aviation, this condition is most commonly associated with hypoxia, where the central portion of the visual field becomes unusable while peripheral vision is initially preserved.
Plain English
You can still see things off to the sides, but the area you'd normally focus on directly in front of you goes dark, blurry, or missing.
Context Anchor
Encountered in night flying, night scanning technique, and discussions of pilot vision in low light.
Derivation
Central refers to the middle of the visual field — the area you use when you look directly at something. Vision is the ability to see. Blindness here means loss of sight in that specific area, not total blindness.
Why Pilots Care
Failure to recognize this effect can cause pilots to lose sight of other aircraft or runway lights when looking directly at them.
Analogy
It is like trying to see a faint star at night: sometimes it appears when you look slightly beside it, but fades when you look straight at it.
Grounding Statement
In darkness, direct staring is not always the best way to see a faint object.
Intuition Check
Central vision blindness does not mean the pilot is blind in the center of vision all the time. It means direct-looking vision can be weak for faint objects in low light.
Example Sentence 1
As the pilot climbed above 14,000 feet without supplemental oxygen, central vision blindness set in, and he could no longer read the airspeed indicator directly in front of him.
Example Sentence 2
Runway edge lights became visible only after the pilot stopped looking directly at them and allowed peripheral vision to take over.