Medically reviewed by Johnstone M. Kim, MD Key Takeaways The pupil controls how much light enters the eye, allowing for clear ...

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 ...

Drug addiction can often be spotted just by the appearance of the individual’s eyes. Of course there are several other physical changes that can give away the fact that someone is struggling with ...

It is the light we think we see that counts. Optical illusions designed to seem brighter than they are make your pupils constrict a little more. This suggests that we have evolved systems for ...

In these experiments, however, Van Gelder, and his research team demonstrated that the constriction of the pupil in the chick eye seems to be regulated by cryptochrome rather than melanopsin, ...

People often mimic each other's facial expressions or postures without even knowing it, but new research shows that they also mimic the size of each other's pupils, which can lead to increased trust.

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 ...

A new study found that we take in a lot of social information, and unconsciously reach conclusions, based on people's pupils. (The Associated Press) The best time to ask your boss for a raise might be ...