Typically, the pupil contracts and dilates depending on the amount of light entering the eye. Neurologists shine light into the eyes of trauma and stroke patients to gauge their light reflex 1 ...

It was previously believed that our pupil size was only affected by three things: light, focusing on nearby objects and cognitive effects.

“We used to think that the pupil was a simple light reflex or that it just indexed arousal,” says Stefan Van der Stigchel, an attention and perception researcher at Utrecht University in the ...

Like the aperture in a camera, the pupil controls how much light reaches the eye. It is therefore fundamental to our vision and how we perceive our surroundings. Three mechanisms that can change ...