Variable angle of strabismus related to timing of opiate ingestion.

Heroin (diamorphine) is a highly addictive opiate with potential for misuse. A small number of reports have linked the commencement of heroin misuse to acute exotropia with diplopia and subsequent withdrawal to esotropia in individuals without previous symptoms.(1-5) We describe a young adult who sought strabismus surgery to correct a large-angle exotropia. Detailed patient history and orthoptic measurements at different times of the day revealed a fluctuating angle of divergence relating to the timing of opiate ingestion, rendering surgery inappropriate. We suggest that opiate misuse, which may not willingly be disclosed by patients, should be specifically asked about before acquired-strabismus surgery is undertaken in adults.