Efferent pupillary defects are caused by problems of sympathetic or parasympathetic innervation or structural iris changes presenting as anisocoria or impaired pupillary light reaction. This overview describes the diagnostic steps for evaluating efferent pupillary disorders and outlines further steps of work-up.
Keywords: Diagnosis; Dorsal midbrain syndrome; Horner syndrome; Third nerve palsy; Tonic pupil.