Endophthalmitis prophylaxis: limited evidence fuels controversy

June 23, 2008

Few well-designed studies evaluate endophthalmitis prophylaxis. Available evidence suggests a role for intracameral cefuroxime. The benefit must be weighed against the potential risk of errors in formulation, however.

Protocols for prophylaxis of postoperative endophthalmitis remain controversial and vary widely among surgeons because of the paucity of Level I evidence to support specific interventions, said Oliver D. Schein, MD, MPH, at Current Concepts in Ophthalmology.

"While a large number of studies have been conducted to investigate enophthalmitis risk factors and prophylactic regimens, most are not rigorously designed, and the prophylaxis studies have been based primarily on surrogate outcomes," said Dr. Schein, the Burton E. Grossman Professor of Ophthalmology, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore. "Therefore, it is possible by reviewing the literature to find some published study that will support virtually any conclusion one chooses about endophthalmitis prophylaxis."

Considering the best available studies, Dr. Schein said that good evidence implicates exposure to vitreous, older patient age, and wound integrity as endophthalmitis risk factors. For prophylaxis, strong evidence exists from Swedish studies using national registry data and from the European Society of Cataract and Refractive Surgeons (ESCRS)-sponsored randomized, prospective, multicenter study that intracameral cefuroxime is protective.

In the ESCRS study, use of intracameral cefuroxime reduced the rate of endophthalmitis five-fold. Intensive perioperative topical treatment with levofloxacin did not significantly reduce the risk of endophthalmitis, and patient age was not a significant risk factor. Intraoperative complications, use of a clear corneal incision, and silicone IOL use also independently predicted risk, however.

Further discussing the ESCRS results, Dr. Schein said that one argument against the purported benefit of intracameral cefuroxime centers on the high background rate of endophthalmitis in the control group, about 1 in 300 cases.

"This information could be used to suggest that intracameral cefuroxime may be beneficial only in settings where the risk of endophthalmitis is very high and where perhaps it is offsetting the effect of poor surgical habits," he said. "However, a counterargument emerges from the Swedish experience, where intracameral cefuroxime was used in 97% of cases and the rate of endophthalmitis was four-fold lower than the reported rates in the United States."

The role of corneal incisions as an endophthalmitis risk factor is controversial, Dr. Schein added. Although some surgeons have used this technique with excellent success and no cases of endophthalmitis, multiple studies have shown clear corneal incision is associated with an excess risk.

Read the complete article in the June 15, 2008 issue of Ophthalmology Times. OT