General anaesthesia for ophthalmic surgery

The majority of ophthalmic surgeries are performed as day cases under topical or regional anaesthesia with or without intravenous sedation. However, general anaesthesia is necessary in certain circumstances e.g. local anaesthetic allergy or patients who are unable to cooperate or to lie flat or still. Patients for ophthalmic surgery are frequently elderly with multiple comorbidities, such as diabetes and hypertension. Patients with rare genetic syndromes may present for eye surgery. Therefore adequate preoperative evaluation and preparation will minimize perioperative complications. The goals of general anaesthesia are smooth induction and emergence, with stable intra-ocular pressure (IOP) and akinesia of the globe. These can be achieved with a combination of intravenous and inhalational agents with or without muscle relaxants and opiates. Use of the laryngeal mask airway has the advantage of causing a smaller rise in IOP on insertion and less coughing on emergence. Total intravenous anaesthesia with propofol and remifentanil has the advantages of causing less postoperative nausea and vomiting (PONV), reduced stress response to airway intervention, rapid recovery and smooth emergence. Some eye procedures require special consideration, for example, strabismus and vitreoretinal surgery involves traction of the rectus muscles producing a higher incidence of oculocardiac reflex and PONV. Most ophthalmic surgery produces mild to moderate pain amenable to non-opioid analgesics. Intraoperative topical and regional anaesthesia reduce postoperative pain and opiate requirement. Open globe injury and a full stomach present unique challenges to prevent increase in IOP as well as protecting the airway.