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42 EW CATARACT October 2013 Preventing endophthalmitis with a review of the evidence by Vanessa Caceres EyeWorld Contributing Writer Intracameral moxifloxacin is injected, as the final step in cataract surgery, through the side port, after hydrating the primary incision. The IOL is depressed during injection so that the antibiotic is delivered into the capsular bag, the avascular sequestered space where the IOL has been implanted. Source: Steve A. Arshinoff, MD Analysis finds it hard to make a conclusion but shows value of intracameral antibiotics A new Cochrane review of intracameral antibiotics to prevent acute endophthalmitis after cataract surgery points out the approach can be effective—although it was hard for researchers to find a large mass of studies to support their use. Still, the investigators note that a clinical trial to show the effectiveness of perioperative antibiotics during cataract surgery would be very large and costly—so it's better to work with existing evidence. The review, published by the Cochrane Database of Systematic Reviews online in July, was led by Watch this video on your smartphone or tablet using your QR code reader. (Scanner available for free at your app store.) Emily W. Gower, PhD, associate professor, Departments of Epidemiology and Prevention and Ophthalmology, School of Medicine, Wake Forest University, Winston-Salem, N.C.1 The study goal was to evaluate the prophylactic effects of perioperative antibiotics for endophthalmitis after cataract surgery. The idea behind the review came from previous research the investigators have done in this area, including an analysis of Medicare claims data that showed an increase in endophthalmitis from 1994 to 2001, Dr. Gower said. For the Cochrane review, investigators searched for clinical trials via a number of different databases. They decided to include randomized controlled trials of adults having cataract surgery. They included trials that evaluated preoperative, intraoperative, and postoperative antibiotic prophylaxis for acute endophthalmitis, but they did not include studies that analyzed antiseptic preoperative preparations such as povidoneiodine. They also decided not to include research focusing on antibiotics to treat acute endophthalmitis only after cataract surgery. Although the investigators found and analyzed nearly 500 potential studies—491, to be exact—to include in their review, there were ultimately only four studies that met their full inclusion criteria. These four studies included 100,875 adults. Two of the studies, both led by N.E. Christy, were published in 1979 and 1986, were set in Pakistan, and used surgical approaches not common today. The two more recent studies were led by G. Sobaci2 in 2003 and the European Society of Cataract and Refractive Surgeons (ESCRS) in 2007.3 The Sobaci study took place in Turkey and focused on a comparison of vancomycin and gentamycin in balanced salt solution irrigating infusion fluid versus balanced salt solution-only irrigating infusion fluid in 644 eyes of 640 participants. All participants received ofloxacin and diclofenac sodium four times at one day preoperatively. Ultimately, the Another study points to prevention with intracameral antibiotic use A recently published study by investigators in Spain found that cefuroxime once again helped to reduce the incidence of endophthalmitis. The study, which appears in the September issue of the Journal of Cataract & Refractive Surgery, compared the rate of endophthalmitis before and after 2005, which marked the use of intracameral cefuroxime in cataract surgery for the investigators. Of 19,463 total patients, endophthalmitis was diagnosed in 44 cases—39 before 2005 and only five cases after. Investigators identified cefuroxime's protective benefits as well as the potential cost savings when cefuroxime was used—a savings of 1,177 Euros for every 182 patients treated. "Intracameral cefuroxime reduced the incidence of endophthalmitis in cataract surgery and had a high clinical and economic impact on its prevention," the investigators concluded. Cochrane authors concluded that the sample size was not large enough to look at statistically significant differences in endophthalmitis rates. The Sobaci investigators concluded that more studies are needed to look at the role between antibiotics in the irrigating solution and incidence of endophthalmitis. In the ESCRS study, multiple sites in Europe and Turkey evaluated the use of intracameral cefuroxime injected at the end of surgery and topical levofloxacin given at specified intervals in the hour before and at the close of surgery in 16,603 participants. The study examined both intracameral cefuroxime and topical levofloxacin—one study group received the former, a second group received the latter, a third group received both, and a fourth group did not receive either treatment. The study found that the use of intracameral cefuroxime significantly reduced the risk for endophthalmitis. Although cefuroxime is widely used in Europe, that's not the case currently in the United States, the investigators noted in their review. Ultimately, only a large clinical trial—one of 100,000 patients or more and that likely will not be done due to cost—would provide exact evidence to assess how well perioperative antibiotic prophylaxis works to prevent acute endophthalmitis, the investigators concluded. Still, they added that practitioners should consider the ESCRS study evidence. Dr. Gower added there are other areas ripe for research in this subject area. "Ideally we need more choices for perioperative antibiotics to prevent endophthalmitis. I would like to see development of a single-use vial of a broader spectrum drug or development of a time-release antibiotic disk that can be inserted at the end of surgery. Of course, we would need to research how these products change the rate of endophthalmitis," she said. Taking a broader look Ophthalmologists with a special interest in infectious-related research applaud the ambitious research work that Dr. Gower and fellow researchers took on with this review. "It highlights how difficult a review like this can be," said Francis continued on page 44