pupil size

As people age, their pupils become smaller, and open less wide in dim light.

Age (years)
 
Diameter of pupil in millimeters
daylight night difference
20 4.7 8.0 3.3
30 4.3 7.0 2.7
40 3.9 6.0 2.1
50 3.5 5.0 1.5
60 3.1 4.1 1.0
70 2.7 3.2 0.5
80 2.3 2.5 0.2

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