Posterior capsule opacification and postoperative endophthalmitis following cataract surgery : predictive and protective factors

Abstract: Modem cataract surgery with implantation of an intraocular lens (IOL) is an increasingly safe and successful procedure, though complications still occur. This thesis addresses the most common complication, posterior capsule opacification (PCO) and the rare but serious complication postoperative endophthalmitis (POE). The pathogenesis of PCO is multifactorial and several surgical and IOL-related factors appear to play an important role in PCO formation. In this project the relation of PCO to IOLs of different materials and design was investigated and, furthermore, the association between PCO and the anterior capsulorhexis position. In a prospective study, patients were randomized to have implantation of a heparin-surface-modified (HSM) poly(methyl methacrylate) (PMMA) IOL, a silicone IOL or a hydrophobic acrylic IOL after phacoemulsification (phaco). The HSM PMMA and the silicone IOL have rounded optic edges and the acrylic IOL has a sharp-edged optic. The PCO was assessed using the Evaluation of Posterior Capsule Opacification (EPCO) analysis system. After 2 years, patients with a hydrophobic acrylic IOL had significantly less PCO compared to those with a silicone or a HSM PMMA IOL. Three years postoperatively, the position of capsulorhexis in the silicone group and the acrylic group, were retrospectively analysed. Patients with the rhexis completely on the IOL optic had significantly less PCO than those with a decentred rhexis. Because of the potentially serious outcome after POE, various prophylactic regimes are used and putative risk factors are analysed. The object of this project was the investigation of the efficacy and safety of a previous undescribed prophylactic mode against POE, an intracameral injection of cefuroxime. Pharmacokinetic data on intraocular cefuroxime was analysed. Visual acuity, endothelial cell loss, laser flare intensity and lgE-mediated hypersensitivity were assessed. Furthermore, the project included a single-centre, retrospective clinical observation study of POE in association with prophylactic intracameral cefuroxime. National data on POE were investigated in a multi-centre prospective observational study and risk factors for POE were analysed in a single-centre case-control study. The studies showed that intracameral prophylactic cefuroxime appears safe and confers protection against POE, the latter in the sense that traditionally common species causing POE, such as staphylococci no longer are main aetiologies. Also, the general incidence of POE was very low.