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How do the pupils of your eye change size? What causes this?

2 doctors weighed in
Dr. Richard Bensinger
Ophthalmology
1 doctor agrees

In brief: Light reflex

When your eye is exposed to light, the dilated pupils receive a signal from the retina, through your brain which tells them to close down to limit the light entry and protect the eye.
The pupils (iris) is a muscular structure in a radial pattern which responds to light signals this way. ;pretty cool!

In brief: Light reflex

When your eye is exposed to light, the dilated pupils receive a signal from the retina, through your brain which tells them to close down to limit the light entry and protect the eye.
The pupils (iris) is a muscular structure in a radial pattern which responds to light signals this way. ;pretty cool!
Dr. Richard Bensinger
Dr. Richard Bensinger
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