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 ...

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 findings from researchers at UCLA Health suggest that measuring changes in how pupils react to light could help predict recovery from depression and personalize transcranial magnetic stimulation ...

The eyes are a window into our autonomic nervous system. Everyone's unique personal history and autobiographical experiences have the power to influence how and when the sympathetic nervous system ...