Both Garcia-Arumi et al.1 and Ellis2 have reported an increased incidence of endophthalmitis with the use of topical anesthesia. Clear corneal incisions3 have been implicated in increasing this incidence due to such factors as the incision opening from pressure of the eyelids during blinking and bacteria from periocular flora gaining entry into the eye through the incision site.
We would like to suggest that the topical anesthetic agent and its vehicle may serve as a reservoir for microbial contamination, with the potential to cause infection. Other disadvantages of topical anesthesia include possible corneal epithelial, corneal endothelial, or retinal toxicity, which is mainly the result of the preservatives in the anesthetic solutions.4 Some agents (eg, proparacaine) can also lead to allergic and idiosyncratic reactions such as periocular swelling, erythema, and contact dermatitis.4 In addition, preoperative instillation of some topical anesthetic agents (eg, lidocaine) can cause burning and stinging and multiple applications can lead to mild corneal haziness during surgery. There is also a potential for cumulative toxicity because several doses of the agent are administered.5 Some surgeons combine topical anesthesia with intracameral preservative-free lidocaine (Xylocaine) during cataract surgery. This may be more toxic to the endothelium because the concentration in the combined technique is up to 250 times higher than in topical anesthesia alone.5
In this context, we would like to mention the unique advantages that microphakonit6,7 and the no-anesthesia cataract surgery technique5 offer in largely avoiding these problems. Microphakonit is bimanual phaco using 700 μm instruments (Figure 1). The incisions used for microphakonit are so small and self-sealing that the chance of their opening as a result of lid or ocular movements is negligible. This makes the postoperative entry of periocular bacteria into the eye a remote possibility. The smaller incisions also decrease the incidence of complications such as postoperative wound leak, shallow chamber, and induced astigmatism. Microphakonit or bimanual phaco using the tiny 700 μm instruments was made possible by decreasing the wall thickness of the phaco tip and the irrigating chopper. The problem of decreased fluid inflow into the anterior chamber was tackled using an end-opening model, removing flow restrictions secondary to the attachment method, and using gas-forced infusion. Incisional outflow was controlled by making all instruments a uniform size and using customized knives.
We realize that at present, one of the incisions has to be enlarged to implant the intraocular lens (IOL). However, as a result of the increasing popularity of microincision coaxial phaco and bimanual phaco, IOLs as small as 1.5 mm to 2.0 mm are now available. More universal recognition of the advantages of microphakonit would provide the impetus to develop IOLs capable of passing through even these ultrasmall incisions without the need to enlarge them. This would make all the advantages of microphakonit available, including that of combating endophthalmitis.
The second strategy that we propose to combat endophthalmitis is the no-anesthesia technique, which avoids the possible side effects of topical anesthesia by excluding the offending agent from the scene of surgery. The surgery has excellent outcomes, with negligible patient discomfort when performed by a skilled surgeon. Adequate patient motivation and a surgeon well-versed in the technique make an ideal setting for the avoidance of adverse postoperative events such as endophthalmitis. Surgeons already performing topical anesthesia surgery have a very short learning curve for conversion to no-anesthesia cataract surgery because the technique remains essentially the same except for the need to particularly avoid excessive manipulations on the conjunctiva and the iris.
We propose that the potent combination of these 2 techniques, along with further developments in IOL technology such as smaller IOLs or injectable IOLs, may help combat postoperative endophthalmitis, which is among the most serious complications of cataract surgery.
1. Garcia-Arumi J, Fonollosa A, Sararols L, et al. Topical anaesthesia: possible risk factor for endophthalmitis after cataract extraction. J Cataract Refract Surg. 2007;33:989-992.
2. Ellis MF. Topical anaesthesia: a risk factor for post-cataract-extraction endophthalmitis? Clin Exp Ophthalmol. 2003;31:125-128.
3. Taban M, Behrens A, Newcomb RL, et al. Acute endophthalmitis following cataract surgery; a systematic review of the literature. Arch Ophthalmol. 2005;123:613-620.
4. Rosenwasser GOD. Complications of topical ocular anesthetics. Int Ophthalmol Clin. 1989;29(3):153-158.
5. Pandey SK, Werner L, Apple DJ, et al. No-anesthesia clear corneal phacoemulsification versus topical and topical plus intracameral anaesthesia; randomized clinical trial. J Cataract Refract Surg. 2001;27:1643-1650.
6. Agarwal A, Jacob S, Agarwal A. Combined microphakonit and 25-gauge transconjunctival sutureless vitrectomy. J Cataract Refract Surg. 2007;33:1839-1840.
7. Agarwal A, Trivedi RH, Jacob S, et al. Microphakonit: 700 micron cataract surgery. Clinical Ophthalmology. 2007;1(3):323-325.