Definition
The smoking, vaping, or other consumption of tobacco products, which introduces carbon monoxide into the bloodstream. Carbon monoxide binds to hemoglobin in place of oxygen, reducing the amount of oxygen carried to body tissues — including the eyes — and degrading night vision even at sea level.
Plain English
Smoking or using tobacco puts carbon monoxide into your blood. That gas takes the place oxygen would normally occupy, so your eyes get less oxygen and you can't see as well in the dark.
Context Anchor
Encountered in night vision and pilot health discussions, especially when preparing for night flight.
Why Pilots Care
It can significantly reduce a pilot's ability to see at night, increasing the risk of disorientation or failure to spot hazards.
Grounding Statement
In night flying, tobacco use matters because the eyes need good oxygen supply to work well in darkness.
Intuition Check
Do not treat tobacco use here as only a long-term health issue. In this context, it can affect a pilot’s night vision and performance during the flight itself.
Example Sentence 1
Because tobacco use reduces night vision, the pilot avoided smoking before her evening cross-country flight.
Example Sentence 2
During the preflight briefing, the instructor noted that even occasional tobacco use can delay the eyes' adjustment to darkness.