Sub-Tenon's versus Topical Anesthesia for Effectiveness of Analgesia During Cataract Surgery: A Systematic Review with Meta-Analysis.

Background: Sub-Tenon's and topical anesthesia are the most common anesthetic techniques employed for cataract surgery. The objectives were to compare the effectiveness of intraoperative analgesia between the two techniques.

Methods: A systematic review was performed of three databases (MEDLINE, EMBASE, CENTRAL) from inception until August 2023. Included were adult patients undergoing routine cataract surgery with sub-Tenon's or topical anesthesia. Excluded were studies using systemic medications and complicated surgeries. The primary outcome was intraoperative analgesia assessed by patient reported pain scores. Secondary outcomes were post-operative pain at 30 minutes and 24 hours, patient satisfaction, surgeon satisfaction and complications. Risk of bias was evaluated using the revised Cochrane risk-of-bias tool for randomized trials (RoB 2). Outcomes were statistically assessed with meta-analyses where able.

Results: Twelve studies with 1370 patients were included in the meta-analysis. Sub-Tenon's block provided better intraoperative analgesia with lower pain scores (SMD -0.53, 95% CI -0.70 to -0.36; p < 0.001) which remained significant on subgroup analysis of six studies with uniform pain scales (MD -0.84, 95% CI -1.22 to -0.47; p < 0.001). Instances of severe intraoperative discomfort requiring rescue regional anesthesia were reported with topical anesthesia. While there was no difference in pain scores at 30 minutes or 24 hours post-operatively, higher patient and surgeon satisfaction was found with sub-Tenon's anesthesia. Serious complications were rare, with a higher reported rate of posterior capsule rupture with topical anesthesia. Only two of fourteen studies were considered an overall low risk-of-bias.

Conclusion: Sub-Tenon's block provides marginally better intraoperative analgesia during cataract surgery over topical anesthesia. Both can be considered effective for uncomplicated cataract surgery.