Administration of intracameral antibiotics, especially vancomycin and moxifloxacin significantly reduces the risk of endophthalmitis compared with using no intracameral antibiotics.
Data were collected from more than 30 international centers where surgeons performed both simultaneous bilateral cataract surgery (SBCS) and unilateral cataract surgery (UCS). The study found that six of 100,989 eyes that received intracameral cefuroxime, vancomycin, or moxifloxacin suffered postoperative endophthalmitis, whereas 12 of 23,847 eyes that did not receive any intracameral antibiotic developed endophthalmitis (p < 0.001).
The infection rate was lower with intracameral vancomycin or moxifloxacin compared with cefuroxime. No cases of bilateral endophthalmitis occurred in 95,254 eyes that underwent SBCS, said Dr. Arshinoff, clinical instructor of ophthalmology, University of Toronto, Toronto.
He identified published reports in which intracameral administration of the following drugs were studied in a total of 122,000 cases.
In all cases, administration of intracameral antibiotics resulted in greater than an 80% reduction in the development of endophthalmitis: vancomycin (a complex glycopeptide) at a dose of 1 mg/0.1 ml balanced saline solution (BSS); cefazolin (a cephalosporin) 1 to 2.5 mg/0.1 ml BSS; cefuroxime (a cephalosporin) 1 mg/0.1 ml BSS; and gatifloxacin or moxifloxacin (fluoroquinolones) at 100 to 500 µg/0.1 ml BSS.
The study centers were members of the International Society of Bilateral Cataract Surgeons (iSBCS). The iSBCS data, from more than 30 centers in 10 countries, indicated that the overall infection rate for all reported cases is 1:6,935. When no intracameral drugs were used, the infection rate was 1:1,987 cases. Vancomycin had an infection rate of 0:19,722 cases, moxifloxacin had 1:35,194 cases, and cefuroxime had 1:9,215.
Preparation, use of moxifloxacin
Dr. Arshinoff said his current antibiotic of choice for cataract surgery is moxifloxacin at a dose of 150 µg/0.1 ml BSS ? 0.2 ml, which he said he was the first to propose and use, and has been using routinely since 2004. He previously used intracameral vancomycin, initially proposed by Howard Gimbel, MD, and James Gills III, MD, in 1992.
Dr. Arshinoff said he changed antibiotics because of genericization and unreliability of vancomycin in Canada after 2002. A number of studies now have demonstrated the safety and efficacy of moxifloxacin intracamerally, prepared by diluting topical moxifloxacin (Vigamox).
"To get 150 µg/0.1 ml, dilute the eye drops to 30% concentration of topical moxifloxacin by adding 7 ml of BSS to the 3 ml contents of a Vigamox bottle (supplied as 500 µg/0.1 ml) in a 12-ml syringe," he said.
Then, 0.5 ml is placed into a medicine cup on the surgical tray by circulator for each case. The scrub nurse draws up 0.3 ml into a TB syringe; the extra allows for loss in the cannula. Dr. Arshinoff explained that if the scrub nurse fills the syringe to exactly 0.3 ml, after the surgeon gets the feel for the necessary travel of the barrel, it becomes easy to inject exactly 0.2 ml and pressurize the eye.
As the last step of surgery, he injects the 0.2 ml through the side port under the distal capsulorhexis edge. Then, he rapidly exits the eye with a final spurt of injection at the incision, making certain that the anterior chamber is left pressurized.
He pointed out that he has performed more than 3,500 cases using this technique. A project currently is under way to prepare a single-use disposable preparation in BSS for intracameral use.
"This study found that every study, irrespective of background risk, showed a greater than 80% reduction of infection rate with intracameral antibiotics in a cumulative total of about 225,000 eyes to date," Dr. Arshinoff said.
"Intracameral moxifloxacin is the easiest of the drugs to prepare, and carries minimal risk of an allergic reaction," he concluded. "The iSBCS intracameral antibiotic study demonstrated a significant benefit, especially of moxifloxacin and vancomycin intracameral injections, despite low background risk."
Steve A. Arshinoff, MD, FRCSCE-mail: email@example.com
Dr. Arshinoff is a consultant to Alcon Laboratories.