Safety and efficacy of topical anesthesia combined with a lower concentration of intracameral lidocaine in phacoemulsification. Paired human eye study

Purpose: To assess the safety and efficacy of phacoemulsification under a topical anesthesia combined with intracameral lidocaine 0.5%. Setting: Department of Ophthalmology, Chang Gung Memorial Hospital, Taoyuan, Taiwan, China. Methods: A prospective randomized double-blind study was designed in which patients had phacoemulsification performed under topical anesthesia (4 drops of nonpreserved lidocaine 2%) with 0.15 mL intracameral placebo (balanced salt solution) in 1 eye (Group 1) and topical anesthesia with intracameral nonpreserved lidocaine 0.5% in the other eye (Group 2). Endothelial changes, including cell density, coefficient variation of cell size, and percentage of hexagonal cells, were measured by noncontact specular microscopy. Preoperative and postoperative best corrected visual acuity was also documented. The degree of pain throughout surgery was ranked on a 10-point visual analog pain scale. Results: Thirty-three patients were recruited. There was no significant difference in preoperative and postoperative mean endothelial parameters between the 2 groups. Furthermore, mean endothelial cell loss was similar. Mild or no pain (score 0 to 1) was reported by 48.5% in Group 1 and 90.9% in Group 2. Patients reported less pain with combined topical and intracameral lidocaine anesthesia (P = .001, Mann-Whitney test). Vision was significantly improved in both groups. However, 1 patient in Group A developed vitreous loss as a result of involuntary eye movement. Conclusion: Combining topical anesthesia with intracameral lidocaine 2% anesthesia was safe and effective in phacoemulsification with intraocular lens implantation.