Under physiological conditions, the pupils are either centrally positioned within the iris or exhibit a slight inferonasal displacement. This positioning reflects the balanced interaction between the sympathetic and parasympathetic components of the pupilomotor system.
Partial attenuation or loss of adrenergic activity disrupts the equilibrium between the sphincter and dilator muscles, resulting in pupillary decentration. Despite this positional shift, the pupil typically retains its circular configuration, and the collarette remains intact.
Pupillary decentration is considered clinically significant when the displacement of the pupillary center exceeds 3% relative to the geometric center of the iris.
