The Comparison of Retrobulbar Block with Topical-Anterior Subconjunctival Anaesthesia for Small Incision Cataract Surgery: A Randomized Control Trial

Abstract

Summary:

Sight and life-threatening complications following retrobulbar block resulted in the emergence of alternative local anaesthetic techniques such as sub-Tenon block, peribulbar, intracameral, sub-conjunctiva and topical anaesthesia. This study compared the visual analogue pain score, comfort score and patients' satisfaction between retrobulbar block and topical- Anterior subconjunctival anaesthesia in patients scheduled for small incision cataract surgery (SICS). This was a single-blinded clinical trial conducted in 62 ASA I-II patients, aged 50 to 90 years scheduled for small SICS, 31 patients were randomly assigned to receive either Retrobulbar Block (RB), or Topical-Anterior Subconjunctival Anaesthesia (TASCA). In the RB group, a mixture of 2% lidocaine, and 3.75IU/mls of hyaluronidase (Wydase), to make up a total volume 4.0 mls was injected into the retrobulbar space. Topical-Anterior Subconjunctival anaesthesia (TASCA) group involved the administration of an initial drop of 2% topical lidocaine prior to the application of the speculum followed by anterior subconjunctival injection of 0.2 ml of 2% lidocaine and maximum total dose of 3 drops (appropriately 40 µL per dose) of 2% topical lidocaine at intervals depending on participant's pain and comfort. We evaluated visual analogue pain scale (VAPS), comfort score and patients' satisfaction during SICS for both groups. A significantly higher number of patients in the TASCA group reported higher intraoperative pain with VAPS ≥5, p <0.001. Chemosis was significantly higher in the RB group, 43.8%, than in the TASCA group 10%, p =0.003. However, the postoperative VAPS, comfort score, and patients' satisfaction were comparable, p>0.05 in both groups. Topical-Anterior subconjunctival anaesthesia was associated with intraoperative pain and lower complication rates compared to retrobulbar block. However, postoperative pain, comfort score and patients' satisfaction were comparable in both groups.