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 |  | A Short Course in Evaluation of Pupil Sizes In the case of brain injury (concussion, for example) the pupils sometimes give us information about where and how severely the brain might be effected. 
   
   
  Normal Responses to Light and dark  
 There are two main pupillary responses to light, the   Direct   and   Indirect  . 
 When a light is shined into the eye, its strongest reaction is from the   Direct Response  , and is just what you expect: the pupil should get smaller when a light is shined dire...Read More
 |  |  |  |  | Tonic Pupil Tonic Pupil 
 The pupil has a decreased or absent light reflex a slow or delayed constriction to near vision and a sluggish dilation in the dark Most of us are not even aware that our pupils dilate and constrict as light changes around us. The pupil regulates the amount of light that enters the eye so it dilates in dark environments and constricts in bright environments. In patients that have a tonic pupil the pupil has a decreased or absent light reflex a slow or delayed constriction to near ...Read More
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