The opposite of dilated pupils are constricted pupils. Constricted, or small pupils, can occur for a variety of reasons including eye injuries, brain trauma, medication side effects and stroke.
Cocaine and methamphetamine abuse can also cause shrinkage of the pupils. Constricted pupils should be examined by a doctor, especially if they're accompanied by symptoms such as dizziness, light sensitivity and blurred vision. If only one pupil is constricted, it may be the result of a rare disorder known as Adie's pupil. Uneven pupils with drooping eyelids may be indications of serious conditions such as Horner's syndrome and third cranial nerve paralysis.