SAN FRANCISCO, California — American cataract surgeons have begun to accept intracameral antibiotic injection as effective prophylaxis for endophthalmitis, but the practical details still need sorting out, new research suggests.
"People are starting to figure out how they're going to implement this. We've been getting emails from physicians and pharmacists across the country, asking questions about our recipe," said lead investigator Neal Shorstein, MD, associate chief of quality for the Kaiser Permanente Northern California Diablo Service Area in Walnut Creek, California.
Dr. Shorstein presented study results here at the American Society of Cataract and Refractive Surgery (ASCRS) 2013 Symposium, and pointed out that American surgeons at the meeting expressed a great deal of interest in the issue. The results were first published in the Journal of Cataract and Refractive Surgery (2013;39:8-14).
ASCRS leaders highlighted the study's findings during a Best of the Best session that concluded the meeting. "We have finally crossed that boundary; we are no longer arguing about whether intracameral antibiotics work, but about which one to use and how to use it," Roger Steinert, MD, from the Gavin Herbert Eye Institute at the University of California–Irvine, said in a video conversation with outgoing ASCRS president David Chang, MD.
After analyzing the outcomes of 16,264 cataract surgeries by 14 Kaiser Permanente ophthalmologists in a single service area of Northern California, the researchers found a 22-fold decline in the rate of clinical endophthalmitis when patients received an intracameral antibiotic (cefuroxime in 2008 and 2009; cefuroxime, moxifloxacin, or vancomycin in 2010 and 2011).
However, until recently, most American cataract surgeons stuck with topical antibiotics.
"I don't know why it took our study to break the ice, but my sense is that it has," Dr. Shorstein said. "I think people were just waiting, for some reason, for that first study showing that the results do work in this country, with the phacoemulsification machines and the techniques that we use here."
Although attitudes have begun to thaw, ophthalmologists in the United States still face several barriers, including the lack of availability of ophthalmic cefuroxime, which has been tested and approved in Europe.
In addition, community ophthalmologists would not have the safety advantage of working with in-house compounding pharmacists and having 0.1 cc doses prepared for off-label intracameral use, Dr. Shorstein said.
Surgeons in the United States often opt for the off-label use of a broad-spectrum fluoroquinolone — 0.5% moxifloxacin hydrochloride (Vigamox, Alcon Laboratories) — which is approved for topical ophthalmic use, Dr. Shorstein explained.
However, that drug only comes in 3 mL bottles — the Kaiser physicians used a 0.1%, 0.1 mL intracameral dose — and the evidence for its efficacy against endophthalmitis is limited and largely presumptive, he said, citing a study on the safety of prophylactic moxifloxacin (J Cataract Refract Surg. 2007;33:63-68).
Dr. Shorstein was quick to point out that only Vigamox — the nonpreserved additive-free version of moxifloxacin — should be used. Alcon also sells moxifloxacin under the brand name Moxeza, but that contains additives associated with severe toxic anterior segment syndrome when injected intracamerally, he noted.
Moxifloxacin vs Cefuroxime
A recent ASCRS press release echoed this warning. It reported that 12 cases of toxic anterior segment syndrome occurred because a pharmacist substituted Moxeza for Vigamox without the surgeon's knowledge.
If used properly, however, moxifloxacin appears to be "a perfectly reasonable" choice for intracameral prophylaxis, Dr. Shorstein said. "It has broad-spectrum coverage, it is readily available in a nonpreserved form, it's easy to dilute, and it has a dose-dependent kill profile, rather than having a time-dependent dose kill characteristic. Cefuroxime is more dependent on the concentration over time."
Currently, there are no data comparing cefuroxime with moxifloxacin intracameral injections. This is one of the things we're looking at now," he said.
Study coauthor Lisa Herrinton, PhD, has obtained National Eye Institute funding for a follow-up study that will be a head-to-head comparison.
"In a year's time, we hope to have some definitive data about this," Dr. Shorstein concluded.
The Permanente Medical Group provided administrative support for this study. Dr. Shorstein and his team have disclosed no relevant financial relationships. Dr. Steinert reports he being a consultant for Abbott Medical Optics, OptiMedica, ReVision Optics, and WaveTec Vision.
American Society of Cataract and Refractive Surgery (ASCRS) 2013 Symposium: Paper session 3-F. Presented April 22, 2013.
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Cite this: Cataract Surgeons Warming Up to Intracameral Antibiotics - Medscape - Jun 06, 2013.