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 ...

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, ...

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 ...

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 ...

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.

The horizontal axis represents the time elapsed following the presentation of the image, while the vertical axis denotes the degree of change in pupil diameter relative to the image presentation. A ...

The pupil not only regulates the amount of light entering the eye, but also reflects the state of the brain: when we are aroused or focused, the pupils dilate. The pupil even changes as mammals sleep, ...

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 ...

You have probably heard the saying that the eyes are the windows to the soul, but now it turns out that they are also connected to how we breathe. Scientists have long studied the size of our pupils ...

Looking deep into your conversation partner's eyes isn't just for lovers — it has a place in the conference room, too. That's according to new research, which found that people are more likely to ...