Randomized controlled trial to evaluate intraocular pressure following sub-Tenon's local anesthesia for cataract surgery: With and without hyaluronidase added to anesthetic solution

AIM: To evaluate effect on intraocular pressure (IOP) during sub-Tenon's local anesthesia (LA) during cataract surgery with 4 ml of anesthetic injected without and with addition of hyluronidase to anesthetic solution. MATERIALS AND METHODS: This randomized controlled study included 65 eyes of 65 patients undergoing phacoemulsification and lens implant for cataract. The patients were randomized to a standardized procedure of administration of 4 ml of sub-Tenon's LA without and with addition of 15 IU/ml hylaluronidase to 2% lidocaine (control group and intervention group respectively). IOP measurements were carried out immediately prior to and at 2, 5, and 10 and 15 min after sub-Tenon's injection using a hand held tonometer (Tonopen). RESULTS: All patients achieved satisfactory akinesia and complete analgesia during surgery. The mean age of patients in control group was 59.56 ± 14.3 years, and 61.77 ± 11.91 years in intervention group (P = 0.507). The mean preinjection and 15 min IOP was 19.16 ± 4.39 and 20.21 ± 5.49 mm Hg, respectively in control group (P = 0.220); and 19.81 ± 3.8 and 19.68 ± 5.19 mmHg respectively in intervention group (P = 0.911). No statistical difference from baseline was detected between preinjection and at 2, 5, 10, and 15 min after injection in control (P = 0.124, 0.310, 0.804, 0.220, respectively) and intervention group (P = 0.367, 0.879, 0.765, 0.911 respectively). CONCLUSION: No significant rise in IOP occurs following injection of sub-Tenon's LA, when up to 4 ml of anesthetic is injected. The addition of hyaluronidase to 2% lignocaine has no beneficial lowering effect on IOP in sub-Tenon's LA. Hence, the practice of addition of this agent may not be necessary during cataract surgery.