Snapshot A 67-year-old man presents to his physician following a right-sided carotid endarterectomy. He reports mild pain at the surgical site but currently does not have any concerns. On physical exam, there is anisocoria with the right eye being miotic. There is also mild ptosis on the right eye as well. Introduction Clinical definition a neurologic syndrome characterized by ipsilateral miosis ptosis anhidrosis Pathogenesis can be caused by a lesion anywhere on the sympathetic pathway supplying the head, eyes, and neck login to view 1 more bullet causes include Pancoast tumor Wallenberg syndrome syringomyelia and cervical cord trauma that affects the login to view 1 more bullet carotid endarterectomy and carotid artery stenting carotid dissection Presentation Symptoms and physical exam miosis resulting in anisocoria secondary to unchecked parasympathetic innervation ptosis due to impaired sympathetic innervation to Muller's muscle generally mild anhidrosis suggests an central or preganglionic lesion