Purpose: To establish the nationwide rate of postoperative endophthalmitis (PE) after cataract extraction (CE) and to study the relationship between PE and type of incision and other possible risk factors.
Design: Prospective, multicenter, comparative, nonrandomized, observational study.
Participants: All cataract surgeries in Sweden performed from January 2002 through December 2004 and all endophthalmitis cases in the same period that were reported to the Swedish National Cataract Register (NCR).
Methods: Through a standard reporting form sent to the NCR, patient and operation technique data were recorded. In addition, PE cases with a traceable number to the main register were collected. Various parameters with a possible impact on endophthalmitis development were evaluated. Univariate analyses and logistic regression were statistical methods.
Main outcome measures: The rate and etiology of PE; possible risk factors pertaining to patient history and operation technique, with a special emphasis on incision type and location; use of injector for the intraocular lens implantation; kind of prophylaxis; and presence of peroperative communication between the anterior chamber and vitreous.
Results: The overall rate of PE was 0.048% (109 cases in 225 471 CEs). Incidences of PE were 0.053% with clear corneal incisions and 0.036% with sclerocorneal incisions (P = 0.14, logistic regression analysis). The corresponding results were 0.040% for superior incisions and 0.055% for temporal incisions (P = 0.14). Communication between the anterior segment and vitreous was found to be a highly significant independent risk factor for PE (P<0.001), as were patient age > or = 85 years (P<0.001) and the nonuse of intracameral cefuroxime (P<0.001).
Conclusions: The overall rate of PE after cataract surgery is low in Sweden, which may be a consequence of the widespread use of prophylactic intracameral cefuroxime. Only a trend for an increased risk of PE was detected for clear corneal and temporal wounds. The present data indicate that the use of clear corneal and/or temporal approaches will result in 1 additional PE case in approximately 5500 procedures on top of the PE rate after sclerocorneal or superior incisions, which was approximately 1 case in 2400 operations.