Currently, there are no published standard guidelines in ophthalmology for antibiotic prophylaxis in regard to endophthalmitis prevention during cataract surgery.1 Many practice patterns exist, including topical antibiotic drops, antibiotics placed in the irrigating fluid, subconjunctival injections of antibiotics, and intracameral antibiotics placed at the time of surgery. Although recent studies have shown a reduction in endophthalmitis rates with the use of intracameral antibiotics, many concerns still exist in regard to the true efficacy and, perhaps more importantly, to the safety of this approach, as no commercially approved intracameral antibiotic is available in the United States.
In the landmark study on prophylactic antibiotic use conducted by the European Society of Cataract & Refractive Surgeons (ESCRS), a five-fold reduction in endophthalmitis rates after cataract surgery was observed in patients who received intracameral cefuroxime (0.07% vs 0.34% incidence).2 One limitation of this study is the use of topical levofloxacin, as moxifloxacin or other fourth-generation fluoroquinolones were not available at the time. Current evidence shows that the newer fourth-generation fluoroquinolones offer a broader spectrum of bacterial coverage, improved ocular penetration, and greater potency against gram-positive bacteria. This raises the question of whether the results of the ESCRS study would have been different had moxifloxacin been the topical agent used.3
Neal Shorstein, MD, and colleagues conducted the first US study evaluating the effects of intracameral antibiotics.4 In their protocol, patients were initially treated with topical antibiotics per surgeon preference. Two years into the study, the surgeons began administering intraocular cefuroxime (1 mg/0.1 mL) in patients without penicillin or cephalosporin allergies and without posterior capsular rupture. The patients were then subsequently given cefuroxime, moxifloxacin, or vancomycin (depending on allergy profiles for each patient) for all comers. The results showed a compelling decrease in endophthalmitis rates between each advancing stage of the study (3.13% vs 1.43% vs 0.14%).4
The most recently published large study on the subject is a meta-analysis by the Cochrane Collaboration, which included four studies, including the ESCRS study.5 The conclusions of the meta-analysis were that clinical trials with rare outcomes such as endophthalmitis require large sample sizes and are very expensive to conduct; thus, it is unlikely that further clinical trials of this nature will be performed. Therefore, physicians were advised to rely on current evidence as the basis for their decision-making in endophthalmitis prevention.5 Criticisms of the Cochrane study include the low number of studies included for analysis due to the inclusion criteria and the large diversity in study design modes, surgical technique, and antibiotic administration in the studies reviewed.6 The meta-analysis did emphasize the global need to decrease the incidence of postoperative endophthalmitis and concluded that intracameral antibiotics appeared to be effective; however, it also presented concern that there was no commercially available single-use intracameral antibiotic preparation.5
Drawbacks to intracameral antibiotic use are mostly related to safety and include the risk of corneal toxicity, toxic anterior segment syndrome, effects on the retina, potential for allergy, compounding errors, and concerns for possible medical-legal ramifications if complications were to occur, as no FDA-approved intracameral antibiotic exists in the United States.1 Questions have also arisen in regard to the duration of intracameral antibiotic within the eye after surgery and if the length of time it endures is adequate to achieve sufficient minimum inhibitory concentration.1 Thomas Liesegang, MD, has brought up the point that most cases of endophthalmitis are due to bacteria present on the ocular surface that enter the eye during wound healing and that the length of duration of an intracameral antibiotic within the anterior chamber would not cover the 7-to-10-day healing time of a clear corneal incision.1
For US surgeons interested in adopting intracameral antiobiotics, options include obtaining antibiotics, such as cefuroxime or moxifloxacin, from a compounding pharmacy or following a protocol used by Steve Arshinoff, MD, a long-time supporter of intracameral antibiotics. Dr. Arshinoff recommends moxifloxacin 300 micrograms/0.2 cc. He currently dilutes 3 cc of moxifloxacin (Vigamox; Alcon) with 7 cc balanced salt solution.6 Of note, Moxeza (Alcon) or other formulations of moxifloxacin are not safe substitutes for intracameral use in the eye and should not be used. A new alternative now exists as a combination preparation of triamicinolone and moxifloxacin, available from Imprimis Pharmaceuticals, but injection through the zonules at the end of cataract surgery is required with this approach.
After many studies and articles examining the use of intracameral antibiotics, the debate continues. As evidenced by the 2007 American Society of Cataract and Refractive Surgery (ASCRS) survey regarding prophylaxis of endophthalmitis after cataract surgery, only 30% of respondents were using intracameral antibiotics, but 82% replied that they would do so if a commercial preparation were available at a reasonable price.7 Hopefully progress will be made in order to achieve the end goal of further decreasing the incidence of postoperative endophthalmitis.
1. Liesegang T. Intracameral antibiotics: questions for the United States based on prospective studies. J Cataract Refract Surg. 2008;34:505-509.
2. Barry P, Seal DV, Gettinby G, et al; for the ESCRS Endophthalmitis Study Group. ESCRS Study of prophylaxis of postoperative endophthalmitis after cataract surgery: preliminary report of principal results from a European multicenter study. J Cataract Refract Surg. 2006;32(3):407-410.
3. O’Brien T, Arshinoff S, Mah F. Perspectives on antibiotics for postoperative endophthalmitis prophylaxis: potential role of moxifloxacin. J Cataract Refract Surg. 2007;33:1790-1800.
4. Shorstein N, Winthrop K, Herrington L. Decreased postoperative endophthalmitis rate after institution of intracameral antibiotics in a Northern California eye department. J Cataract Refract Surg. 2013;39:8-14.
6. Arshinoff S. Cataract surgery: Perioperative intracameral antibiotics should be standard practice. Ophthalmology Times. May 2014.
7. Chang DF, Braga-Mele R, Mamalis N, et al; ASCRS Cataract Clinical Committee. Prophylaxis of postoperative endophthalmitis after cataract surgery: results of the 2007 ASCRS member survey. J Cataract Refract Surg. 2007;33:1801-1805.