If the anisocoria is still present at the time of your examination, and both pupils constrict normally to light, rule out Horner syndrome with apraclonidine instillation, which should not cause reversal of anisocoria
If the mydriatic pupil fails to constrict normally to light, rule out third nerve palsy, tonic pupil, pharmacologic mydriasis, and iridoplegic mydriasis with appropriate diagnostic maneuvers
If you diagnose episodic mydriasis, advise the patient that this is a benign condition that usually occurs without explanation or as part of migraine or a seizure, and may occur again