Background: Cataract is defined as loss of transparency of the natural lens and is usually an age-related phenomenon. The only recognized treatment available for cataract involves surgery. An ideal anaesthetic should allow for pain-free surgery with no systemic or local complications. It should be cost effective and should facilitate a stress-free procedure for surgeon and patient alike. Topical anaesthesia involves applying anaesthetic eye drops to the surface of the eye prior to and during surgery. This has found large acceptance especially in the USA where it is used by 61% of cataract surgeons. Many surgeons who perform cataract surgery under topical anaesthesia also use intraoperative supplementary intracameral lidocaine (injected directly into the anterior chamber of the eye). The benefits and possible risks of intracameral lidocaine have been assessed by a number of randomized controlled trials, but the results have been conflicting and many of the endpoints have been heterogeneous.
Objectives: The primary objective of this systematic review was to assess pain during surgery and patient satisfaction with topical anaesthesia alone compared to topical anaesthesia with intracameral anaesthesia for phacoemulsification. The secondary objectives were to assess adverse effects and complications attributable to choice of anaesthesia and the need for additional anaesthesia during surgery.
Search strategy: We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2006, Issue 2), MEDLINE (1966 to May 2006), EMBASE (1980 to May 2006) and LILACs (1982 to 3 May 2006). We also searched the reference lists of the identified studies and the Science Citation Index. We did not have any language restriction.
Selection criteria: We included only randomized controlled trials (RCTs) comparing topical anaesthesia alone to topical anaesthesia with intracameral lidocaine.
Data collection and analysis: Two authors independently assessed trial quality and extracted data. For dichotomous outcomes data were presented as odds ratios. For continuous outcomes the weighted mean difference was employed. A random-effects model was used unless there were fewer than three trials in a comparison, where a fixed-effect model was used. We explored heterogeneity between trial results using a chi-squared test.
Main results: A total of eight trials comprising of 1281 patients were identified for analysis. Our data comparison showed a significantly lower intraoperative pain perception in patient groups using supplementary intracameral lidocaine, although the difference was small. No significant difference was demonstrated between the groups receiving topical anaesthesia alone and topical combined with intracameral anaesthesia in terms of the need for supplemental anaesthesia, intraoperative adverse events or corneal toxicity.
Authors' conclusions: The use of intracameral unpreserved 1% lidocaine is an effective and safe adjunct to topical anaesthesia for phacoemulsification cataract surgery.