The condition can be determined by looking at the pupil, which is the hole in the center of the iris and has a normal diameter of 2-5 mm. The normal pupil is round and equal in size bilaterally. Unequal pupil size bilaterally suggests intracranial disease, such as traumatic brain injury, brain tumor, central neurosyphilis, cerebral hernia. Dilated pupils are seen in trauma, cervical sympathetic nerve irritation, glaucoma, optic nerve atrophy, atropine. Bilateral pupil dilation with loss of light reflex is seen in near death. Pupil constriction, seen in organophosphorus pesticide poisoning, etc.