We report on a series of patients with acute strabismus related to heroin and methadone intake or withdrawal, discuss possible mechanisms involved in this clinical picture and make recommendations for work-up and referral.Retrospective study.Five patients presented with acute esotropia within days of heroin withdrawal, and two patients developed exotropia related to heroin or methadone intake. Neurological work-up and neuroimaging was non-contributory in all four patients who were examined.Acute esotropia with double vision is a disturbing side effect of heroin withdrawal, and, similarly, acute exotropia may be related to heroin intake. In the absence of focal neurological signs, further work-up is not mandatory. Referral to a specialised orthoptic service is beneficial in offering the patient symptomatic treatment and reassurance, thus supporting successful withdrawal therapy.