In normal conditions, the pupils are round in shape with even edges. Deformations of pupils in most cases are associated with local diseases of the iris. But such deviations can also take place in the dysfunction of the innervation components of the pupil motor system at all levels. It is necessary to distinguish the difference between the pupil deformation as a result of local disease or disease of the internal organs affecting the central nervous system.

Changes in the pupil observed in one eye in most cases are the symptom of the disease and when observed in both eyes, may be an indicator of hereditary predisposition. There are eight types pf pupil deformations: