Safety and efficacy of intracameral injections of preservative - free lidocaine as an adjuvent to topical anesthesia to reduce intraocular sensation versus peribulbar anesthesia

ABSTRACT

This study was done to evaluate the efficacy and safety of intracameral lidocaine in cataract surgery compared to peribulbar anesthesia. This study was carried out on rabbits [n = 20] and patients [n = 160]. Our primary concern was the potential for corneal toxicity from the intracameral lidocaine. The preliminary study with rabbits showed no significant difference in corneal endothelial toxicity between the 20 rabbit eyes injected with 1% preservative-free lidocaine and the 20 eyes injected with BSS [p = 0.42]. As regards the human studies, a total of 160 cataract patients [160 eyes] participated. Eyes were classified to two groups one group [n = 80] received 0.2 ml intracameral 1% unpreserved lidocaine combined with topical anesthesia [bupivacaine]; the other group [n = 80] received a peribulbar block with a sharp 26-gauge needle using a solution of lidocaine 2% [3 ml], bupivacaine 0.5% [2 ml], and hyaluronidase [wydase] 150 U before phacoemulsification with sclerocorneal tunnel incision .Duration of surgery was measured; implicit time and amplitudes of the b-waves of the photopic electroretinogram [ERG] potentials [single-flash ERG and the 30-Hz flicker ERG] were recorded; frequencies of intraoperative problems, complications, intraoperative, and postoperative pain were evaluated. Surgeon assessments of operative conditions and patient cooperation were recorded. The attending anesthesiologist recorded any increase in pulse or increase in blood pressure. After lidocaine anesthesia combined with topical anesthesia, similar complications were found, longer operation time [p < 0.001], and significantly better visual acuity immediately after surgery [p < 0.001]. The ERG amplitudes were not significantly reduced after 0.2 ml intracameral lidocaine half an hour after surgery [p > 0.05]. The surgeon assessment showed more patient cooperation in the peribulbar group [p = 0.012]. No patient in either group was rated as poorly cooperative. Intracameral lidocaine 1% combined with topical anesthesia can be recommended as an alternative procedure to peribulbar anesthesia in cataract surgery especially in the following situations in patients with high myopia, fear of syringes, or prolonged coagulation