Local anesthesia for cataract surgery

Abstract

Various aspects of local anesthesia for cataract surgery, such as the anesthetic agents and their interaction with ocular nerve supply, anesthesia requirements, available clinical techniques and their inherent complications are reviewed. A comparative evaluation of clinical techniques in terms of efficacy, akinesia, and patient-perceived pain during both anesthesia administration and intraoperative cataract surgery is presented, along with the prevailing practice patterns of anesthesia techniques among refractive surgeons in the United Kingdom and United States. More randomized clinical trials are needed to facilitate statistical methods of metaanalysis to establish convincingly the overall benefits and efficacy of the various local anesthesia procedures in cataract surgery. The wide scope of the present review is of relevance in structuring ophthalmology and anesthesia specialist training programs for junior staff.

Comparison of peribulbar and retrobulbar regional anesthesia with bupivacaine in cats

“…8 In the present study, the palpebral reflex was not affected (except for 1 PBA-treated eye). In humans, RBA typically is accompanied by a separate injection to block this branch of the facial nerve and prevent patients from blinking.…”

“…8,13,18,44,45 The trochlear, abducens, and oculomotor nerves innervate extraocular muscles, and the oculomotor nerve supplies the iris sphincter muscle. All of these nerves, except the trochlear nerve, pass inside the muscular cone.…”

“…Therefore, injecting anesthetic inside the cone can be expected to provide anesthesia and akinesia of the globe. 8,10,33 Ptosis of the eyelid results from paralysis of a branch of the oculomotor nerve, which innervates the levator palpebrae superioris muscle, 33,44 and was seen in most (5/6 for RBA and 6/6 for PBA) of the injected eyes, which suggested appropriate technique and adequate administration of anesthetic.…”

“…In humans, RBA typically is accompanied by a separate injection to block this branch of the facial nerve and prevent patients from blinking. 8,9 However, for PBA, the larger volume provides rostral spread to the eyelids, which results in a block of the orbicularis muscle of the eyelids and thereby avoids the need for an additional eyelid block. 8,10 The reason that most of the peribulbar injections in the present study did not eliminate the palpebral reflex could have been the smaller volume used in comparison to orbit size or insufficient rostral drug delivery.…”

“…[1][2][3][4][5][6][7] Additionally, these techniques provide excellent extraocular muscle akinesia that can replace the use of neuromuscular blocking agents and avoid the need for positive pressure ventilation, both of which are often required for intraocular surgery. 1,[7][8][9][10] As with other regional anesthetic techniques, use of RBA and PBA may reduce the requirements for general anesthetic agents during surgery and thus reduce the adverse effects of these drugs. [11][12][13] Finally, these techniques reduce the incidence of the oculocardiac reflex, which can result in severe bradyarrhythmias and, rarely, asystole.…”