By Lisa B. Arbisser, MD
This retrospective cohort study published in the December 2011 issue of the Journal of Cataract & Refractive Surgery reports that the risk for postoperative endophthalmitis following immediately sequential bilateral cataract surgery (ISBCS) appears to be at least as low as and possibly lower than published rates for unilateral surgery, particularly when recommended precautions are taken, and that intracameral antibiotics significantly reduce the risk for postoperative endophthalmitis.
These results are based on statistical analysis of a literature search and a survey of members of the International Society of Bilateral Cataract Surgeons (iSBCS) conducted by Steve A. Arshinoff, MD, FRCSC, and his colleague, Paul A. Bastianelli, BSc.
The survey showed no cases of bilateral endophthalmitis occurring among 95,606 eyes (a sample size more than six times larger than the ESCRS endophthalmitis study) that had immediately sequential bilateral cataract surgery. The overall rate of postop infection was calculated as 1 in 5,759.
The literature review, which evaluated the recent incidence of postop endophthalmitis in unilateral cataract surgery with and without the use of intracameral antibiotics, showed infection rates were significantly reduced with intracameral antibiotics to 1 in 14,352 cases.
The authors note that in each of the four cases of bilateral simultaneous endophthalmitis reported in the past 60 years, there were breaches of aseptic protocol.
Given this surprisingly low infection rate, the authors suggests that in the best of hands and using intracameral antibiotics prophylactically, endophthalmitis can be reduced to between 1 in 10,000 using intracameral cefuroxime and 1 in 55,000 using intracameral vancomycin or moxifloxacin. They report that adding antibiotics to the irrigating solution appears to have little beneficial effect.
I believe this study definitively shows the benefits of intracameral antibiotics and sets out the basic tenets for safe bilateral sequential same-day surgery which, were it not for Medicare payment schedules, should be gaining ground in the United States as it is around the world.
The authors advocate for moxifloxacin as the intracameral antibiotic of choice. Both moxifloxacin and vancomycin have broader spectra of activity against common endophthalmitis pathogens and less reported bacterial resistance than cefuroxime. Unlike vancomycin and cefuroxime, moxifloxacin shows dose-dependent rather than time-dependent kinetics in bacterial killing and antinuclear rather than anti-cell-wall efficacy.
Moxifloxacin has a low risk for allergy (especially compared with cephalosporins), covers the broadest spectrum of potential endophthalmitis pathogens and is the simplest to prepare, making dilution errors unlikely. In the event of failure, moxifloxacin is most likely to yield a resistant strain of Staphylococcus, which will probably be very sensitive to the usual anti-endophthalmitis drugs of choice (vancomycin and ceftazidime), which act by completely different mechanisms than moxifloxacin.