Case-control study of endophthalmitis after cataract surgery comparing scleral tunnel and clear corneal wounds

PURPOSE: To study the possible association between clear corneal incision with or without placement of a suture during cataract extraction and postoperative endophthalmitis. DESIGN: Retrospective, comparative, case-controlled study. METHODS: Thirty-eight patients treated for culture-positive, acute postcataract surgery endophthalmitis, and 371 randomly selected control patients who underwent uncomplicated cataract surgery in the referring community were studied. Incision type and use of suture during cataract surgery of endophthalmitis patients were compared with the controls. The data were analyzed using logistic regression methods. RESULTS: Of the 38 patients with endophthalmitis, 17 patients (45%) had clear corneal incisions and 21 patients (55%) had a scleral tunnel incision. In 371 controls, 76 patients (20%) had clear corneal incisions and 295 patients (80%) had scleral tunnel incisions. Clear corneal incision was associated with a threefold greater risk of endophthalmitis than was scleral tunnel incision (Odds Ratio, 3.36, 95% Confidence Interval = 1.67 to 6.78). The type of incision was significant (chi(2) = 11.53, P =.0007); a clear corneal incision was more frequently associated with endophthalmitis. A subgroup analysis revealed that the presence or absence of a suture was not significant (chi(2) = 1.31, P =.2524). CONCLUSIONS: In this retrospective, case,controlled study, clear corneal incisions were found to be a statistically significant risk factor for acute postcataract surgery endophthalmitis when compared with scleral tunnel incisions.