Pupillary response in those with PTSD differs from people who have not experienced traumatic events. The pupils of those with PTSD failed to show sharp constriction caused by light changes, and more enlargement when exposed to emotional stimuli that other participants. Patients with PTSD not only showed an exaggerated response to threatening stimuli but also to stimuli that depicted positive images.
The research, led by Dr Aimee McKinnon at Cardiff University and published in the journal Biological Psychology, looked for traces of these traumatic events in the eyes of patients who were suffering from PTSD by measuring the pupil of the eye while participants were shown threatening images such as vicious animals or weapons, as well as other images that showed neutral events, or even pleasant images.
Read more at: https://neurosciencenews.com/eye-trauma-mark-16659/