What A Concussion Is And How To Detect It

PUPILLARY ABNORMALITIES

The pupils are the part of the eyes that control how much light gets through to the retina (the part of the eyeball that sees the image).  Pupils constrict (adjust to become a smaller opening) to prevent too much light from getting in (like during a bright noonday sunshine), which would hurt our eyes and can actually cause damage to our eyes.  They also dilate (adjust to become a larger opening) to allow more light to reach the retina, and allow us to see even in environments with less light, like in a dark room.  Simply put, our pupils should constrict when it is exposed to light, and dilate when there is too little light.  Of course, the dilation or constriction of the pupils will be reactions that are still controlled by the brain.

A person with a concussion will sometimes have their brain unable to process the stimuli of whether or not the environment is bright or dark.  Usually, a person with a concussion will have pupils that are dilated, even when you shine light directly onto the eyes (as you may have seen some Emergency Responders do).  This is because even if the eyes can see the light, the brain is unable to process that stimulus, so the brain thinks it is still dark, so it commands the pupils to dilate.  Another indicator that the person has a concussion is when the pupils are of unequal size, one dilated while the other constricted.  If the pupils remain dilated even when directly shone with light, or if the pupils are unequally dilated, the person needs medical attention immediately.