The use of blunt instead of sharp needles for ophthalmic local anesthesia techniques has reduced the incidence of injury to intra-orbital structures. This case review of complications from blunt needle sub-Tenon's block suggests that sight-threatening or even life-threatening complications can still occur.
Patients undergoing cataract surgery using peribulbar block were allocated randomly to self-administer doses of either midazolam 0.1 mg or propofol 3.3 mg without a lock-out facility; in the control group the syringe was charged with saline, not as a placebo, but to "blind" the surgeon and the nurse observer. For midazolam and propofol, median doses were 2.54 (0.1-6.0) mg and 87.4 (0-145) mg, respectively. Patient-controlled sedation significantly reduced the level of anxiety, with median visual analogue anxiety scores in the midazolam, propofol and saline groups of 5 (0-38) mm, 5 (0-25) mm and 15 (0-92) mm, respectively (P < 0.05). Some patients did not administer the sedative when available while others in the saline group would have benefited from anxiolytic drugs. While both drugs prevented an increase in heart rate, only midazolam prevented an increase in arterial pressure during surgery.
Cataract surgery is routinely performed under local anaesthesia. With modern surgical techniques, adequate operating conditions can often be provided by topical anaesthesia alone. For more complex procedures and for prolonged operations such as vitreo-retinal surgery a local block is required. Historically, the sharp needle techniques of retrobulbar and peribulbar eye block have been used. However, the occurrence of rare but sight-threatening complications such as retrobulbar haemorrhage and globe perforation have led to the adoption of the technique of sub-Tenon's block, which avoids the use of sharp needles. A thorough knowledge of ocular anatomy is essential before proceeding with any eye block technique. Patients who receive local anaesthesia for ocular surgery require careful preoperative assessment and stabilization of concomitant medical conditions. The intended procedure should be explained to the patient to ensure their cooperation and reduce anxiety.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.