On average, how long does it take one's pupils to dilate when they see an object of interest?

Question

And, does the rate of pupil dilation depend on age? Does it slow with increasing age?

Answer 1

Your pupil dilation occurs when exposed to darkness.  Try it for yourself.  When you are in a dark room, your pupils dilate and when you are outdoors or in the light, they constrict.  When your pupils fail to adjjust to light changes, it means there is a neurologicalcal problem.

With aging, the pupil of the eye reacts more slowly to changes in light.

Answer 2

It takes less than 1 second (less than 300 milliseconds).  Younger patients will have a more significant and faster pupil dilation/constriction than older individuals.  All reflexes slow down with age in response to both light and varying distances.