1. Disorders of the parasympathetic outflow (iris sphincter muscle disorders): lesions of the oculomotor nerve, tonic pupil, Adie's pupil syndrome. 2. Disorders of the sympathetic outflow (iris dilator muscle) Horner's syndrome (neuron I, II, III). 3. The afferent pupillary defect (lesions of the optic nerve, the chiasm and the optic tract): amaurotic pupil rigidity, amblyopic pupil disturbance, bitemporal pupil rigidity, homonymous hemianopic pupil rigidity, Argyll-Robertson pupil.