Medically reviewed by Christine L. Larsen, MD Key Takeaways Medications, trauma, and medical conditions can cause miosis or ...

Opioids can cause small pupils, but so can several other things. If you’re concerned that someone is misusing opioids, there are other signs to look for. Share on Pinterest Chelsea Victoria/Stocksy ...

A function of the body that happens automatically without a thought, was considered to be impossible to replicate at will. Yet a 23-year-old student in Germany can shrink and enlarge his pupils on ...

New pupillometry research reveals how post-traumatic stress disorder (PTSD) may affect both branches of the autonomic nervous system. By measuring how someone's pupils dilate and constrict in response ...

New pupillometry research reveals how post-traumatic stress disorder (PTSD) may affect both branches of the autonomic nervous system. By measuring how someone's pupils dilate and constrict in response ...

The iris is a structure behind the transparent cornea of the eye. It has a circular opening called the pupil that changes size in response to the light level. Your pupils are usually the same size as ...

Movie demonstrating the increase in accommodative eye vergence and pupil constriction when the fixating eye (left side of image, right eye of subject) is exposed to -5D defocus. The occluded eye ...