In a somewhat surprising phenomenon, measuringpupil sizecan be used to objectively identifysleepinessand the degree ofsleep deprivation.
It may correlate with the function of the central nervous system.
How does this work?
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Learn about pupillometry and how this measurement may be used to identify how sleep deprived a person is.
What Is Pupillometry and Why Does Pupil Size Matter?
Not only the size but how the pupil changes, can be meaningful.
During periods of rest, or conversely, during periods of activity and arousal, these influences will change.
A well-rested individual can maintain constant pupil size in darkness for 15 minutes.
As you become more sleep deprived, your pupil size will become less stable.
It fluctuates (or oscillates), becoming subtly bigger and smaller rather than maintaining its size.
The muscles themselves may tire and the ability to keep the pupil open may fade.
Therefore, both pupil size and stability can objectively identify sleepiness and sleep deprivation.
You might imagine how it could be used, however.
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