How the eye works at night
Rods, cones, dark adaptation, and the scanning technique that makes night vision usable.
13 min read · Night flying
After this lesson you can
- Explain why looking straight at a faint light at night makes it disappear, and what to do instead.
- Describe how long dark adaptation takes and how quickly a single bright light can undo it.
- Name the three types of vision (photopic, mesopic, scotopic) and the light conditions that produce each.
- List the personal factors -- hypoxia, smoking, alcohol, fatigue -- that measurably degrade night vision.
The airplane does not know whether it is dark outside. It responds to the controls exactly the same way at 2 a.m. as it does at 2 p.m. The pilot is what changes: at night, the eyes that do most of the daytime seeing become the least useful tool in the cockpit, and a different, less familiar visual system has to take over.
None of this is exotic. It is straightforward retinal anatomy, and every part of it produces a concrete cockpit habit: where to point your eyes, how long to look, how bright to keep the panel lights, and what physically destroys the night vision you just spent thirty minutes building.
The rest of this lesson
- 1.Two receptors, two jobs
- 2.Photopic, mesopic, and scotopic vision
- 3.The night blind spot and off-center viewing
- 4.Dark adaptation
- 5.Scanning at night
- 6.What degrades night vision from the inside
- 7.Empty-field myopia
These 7 sections, their figures, the checks along the way and the end-of-lesson quiz come with the CPL track. Paid once, yours for good.
Key terms
Try to recall each definition before turning the card.