Definition
The process by which the eyes adjust to low-light conditions, increasing their sensitivity so that objects can be seen at night. Full night adaptation typically takes about 30 minutes in darkness and can be lost in just a few seconds of exposure to bright white light.
Plain English
It is the time your eyes need to get used to the dark so you can see properly at night. Once your eyes are adjusted, even a quick flash of bright light can undo it and you have to start over.
Context Anchor
Encountered in night flying, instrument flying, and spatial disorientation discussions, especially when a pilot must rely on vision in low-light conditions.
Derivation
From Latin 'adaptare', meaning 'to fit' or 'to adjust to'. The eyes are literally fitting themselves to the darker environment.
Why Pilots Care
Allows pilots to maintain visual references and detect hazards in darkness, reducing risk of spatial disorientation.
Analogy
It is like walking from a sunny ramp into a dark hangar. At first you can barely see, but after a few minutes shapes and details begin to appear.
Grounding Statement
After bright light, your eyes need time in darkness before they can pick up faint lights and shapes well.
Intuition Check
Night adaptation is not just “getting used to night” mentally. It is a real physical adjustment in your eyes, and bright light can partially undo it.
Example Sentence 1
Before the night cross-country, the pilot avoided bright lights for half an hour to preserve night adaptation.
Example Sentence 2
Poor night adaptation reduced the pilot's ability to spot other traffic during the night approach.