Topical anesthesia for combined phacoemulsification and posterior vitrectomy

Abstract

We would like to comment on the article by Yepez and coauthors1 describing the use of topical anesthesia in performing phacoemulsification, intraocular lens (IOL) implantation, and posterior vitrectomy in 45 eyes of 45 patients. Although all patients had grade 2 (mild) pain and discomfort during pars plana sclerotomies, external bipolar cautery, and conjunctival closure, no patient required other types of additional intraoperative anesthesia through the retrobulbar or peribulbar routes. The 2 main advantages of topical anesthesia in intraocular surgery are quick visual recovery and avoidance of needle-related complications associated with the injection of local anesthesia. In 22 patients (48.9%), sulfur hexafluoride gas was used after vitrectomy. This means that the advantage of speedy visual recovery after topical anesthesia is not applicable in this group of patients. Moreover, the other patients are unlikely to be benefited, as the underlying vitreoretinal pathology limits the possibility of rapid visual recovery. Certainly the authors had demonstrated the feasibility of topical anesthesia in this combined anterior and posterior segment surgery. However, other types of local anesthesia (e.g., through the sub-Tenon's route2,3) have also been demonstrated to be safe and provide good anesthesia as well as akinesia. The latter is not provided by topical anesthesia. During cataract surgery under topical anesthesia, patients are usually asked to fixate by looking into the light of the operating microscope. During the subsequent posterior vitrectomy, patients cannot use the microscope light as a fixation target, as intraocular illumination is used instead. Without a fixation target, the eyes may move around, especially when the procedure lasts longer, as in the case of combined anterior and posterior segment surgery. Although the instruments passing through the 2 superior sclerotomies during posterior vitrectomy can help to keep the eyes steady, any sudden movement of the eyeball may directly or indirectly increase the chance of iatrogenic complications, such as retinal tear and hemorrhage. In conclusion, we congratulate Yepez and coauthors on their study describing topical anesthesia in combined cataract surgery and posterior vitrectomy. However, the role of topical anesthesia in this setting needs further evaluation. Alvin K.H. Kwok FRCS Pasco Tam DO, MSc Dennis S.C. Lam FRCS, FRCOphth aHong Kong, China