July 16, 2012 
Mydriasis or dilatation of the pupil is normal in children. Physiological causes are darkness and simpatico tonus (fear, pain, excitement). In practice, the most frequent cause of mydriasis is the instillation mydriatics (atropine and related substances), acute glaucoma, contusion of the eyeball, epidural or subdural hematoma, deep anesthesia, and a wide pupil is also a sign of death. The pupil of the blind eye is not wide due to the consensual pupil reaction.