The Norwich Trabeculectomy Study: Long-term Outcomes of Modern Trabeculectomy with Respect to Risk Factors for Filtration Failure

Objective: The aim of the study was to evaluate the long-term outcomes of a large series of ‘modern’ trabeculectomies with specific respect to traditional risk factors for failure. Methods: 636 consecutive ‘modern’, augmented ‘safe-technique’ trabeculectomies performed over an 11-year period (1998-2008) were assessed in a single centre, observational, cohort study. Traditional risk factors for failure (previous surgery, long-term exposure to topical medication, young age, secondary glaucoma and trainee surgeon) were assessed using various success outcome criteria. Success survival was defined with respect to various intraocular pressure (IOP) targets, using criteria for both complete and two categories of qualified success. A multivariate logistic regression analysis was performed to account for the significant number of patients with more than one risk factor. Results: The mean follow-up period was 65.5 (± 35.7) months. At final follow-up the mean IOP for all eyes was reduced from 23.4 (± 6.2) mmHg pre-operatively to 11.9 (± 4.2) mmHg (p