Holmes-Adie syndrome (MONDO_0018690) is a rare syndrome characterized by an abnormally dilated pupil, hypoflexia, and diaphoresis. The syndrome is usually caused by a viral or bacterial infection. The abnormally dilated pupil is caused by damage to postganglionic parasympathetic fibers innervating the eye. Also known as: Adie Syndrome, Adie pupil, Adie syndrome, Adie's pupil, Adie's pupil or syndrome, Adie's pupil syndrome, Adie's syndrome, tonic pupil.