What information can we give to the patient about the risks of strabismus surgery.

I hope to report the type, incidence, and clinical outcomes of severe complications from strabismus surgery in the United Kingdom and to help in the discussions involved in the consent process. The main part of the talk will revolve around a BOSU (British Ophthalmic Survey Unit) investigation. Cases were identified prospectively between 1 September 2008 and 31 August 2010. Questionnaire data were requested at the time of the complication recognition and at 6 months' follow-up. Outcome was graded I-V, with a poor or very poor outcome meaning either loss of corrected visual acuity or primary position double vision. A total of 60 completed reports of adverse events and complications were received during the study period. During the same time, ∼24 000 strabismus surgeries were carried out in the United Kingdom, yielding an overall incidence of 1 in 400 operations (95% binomial confidence, 1 per 333-500 operations). The most commonly reported complication was perforation of the globe (19 (0.08%)), followed by a suspected slipped muscle (16 (0.067%)), severe infection (14 (0.06%)), scleritis (6 (0.02%)), and lost muscle (5 (0.02%)). Overall, complications were reported in adults and children in equal numbers; however, scleritis was significantly more common in adults. A poor or very poor clinical outcome was recorded as 1 operation per 2400. The study limitations are as follows: the denominator was extrapolated from the number of surgeries in England, and there was an almost certain underreporting of cases. Complications with the potential for a poor outcome are relatively common, but the final clinical outcome is good in the majority of cases.