Anaesthesia-related diplopia after cataract surgery

Editor—We were interested in Gomez-Arnau and colleagues’¹paper, which reported incidences of anaesthesia-related diplopiaof 0.39 and 1% following 2024 retrobulbar and 98 peribulbarblocks. Nineteen anaesthetists had performed these blocks duringa 3 yr period. Our own retrospective audit of 940 consecutiveperibulbar blocks for cataract surgery, performed personallyor directly supervised by four anaesthetists between June 1999and June 2000, found six cases of persistent postoperative verticaldiplopia—an incidence of 0.64%.² All our patients with diplopia showed an immediate postoperativehypertropia in the injected eye, and evidence of muscle weakness,which changed over the subsequent 4–6 weeks to hypotropiawith restricted elevation of the affected eye. This suggeststhat the inferior rectus was the affected muscle. All the