Pupils are Windows to the Soul! Or Are They?

Jason Hack, MD, FACEP
Brown University, Department of Emergency Medicine


“I did not know that!”

Belladonna is an Italian word meaning ‘beautiful woman.’  Historically, extract from the belladonna plant was used to dilate women’ s eyes as the resulting mydriasis was considered attractive.  Antimuscarinic effects of atropine in the belladonna plant acts locally, interfering with the receptors in the eye that balance miosis with mydriasis. The one-sided tug-of-war results in big pupils.

Did you know that the size of the pupil decreases by 0.04 mm each year after puberty?

This seems to come from “a progressive decrease in centrally controlled level of sympathetic activity…Older people consequently have smaller pupils than do younger people”.*

*Clinical Neuro-Ophthalmology: A Practical Guide. Ed Ulrich Schiefer, Helmut Wilhelm, William Hart. Chapter 5. Springer, 2007.

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