National audit of the outcome of primary surgery for rhegmatogenous retinal detachment. I. Sample and methods.

PURPOSE: This national study was designed to audit anatomical outcome and complications relating to primary surgery for rhegmatogenous retinal detachments. This paper presents survey methods, characteristics of participating consultants and the demographic and clinical characteristics of the patient sample. METHODS: Two surveys were undertaken. The first identified consultants who at the time performed retinal detachment surgery in the National Health Service. These surgeons formed the sampling frame for a nationwide cross-sectional clinical study that audited the outcomes of primary surgery for rhegmatogenous retinal detachments. Consultants selected patients according to the study eligibility criteria and data were collected by self-administered postal questionnaires. A validation exercise was carried out to examine selection bias and reporting accuracy. RESULTS: Only 256/671 (38%) of UK consultants, who responded to the first survey, indicated that they performed retinal detachment surgery on NHS patients. Annual activity varied between 0 and 400 primary procedures for rhegmatogenous retinal detachments. Seven hundred and sixty-eight eligible patients from 167 consultants were recruited for the clinical study. Twenty per cent of patients had a single retinal break with less than one quadrant of associated detachment and 45% had single or multiple breaks within the same quadrant and/or less than two quadrants of associated retinal detachment. Over 50% patients had single or multiple horseshoe tears. Validation studies suggested that there was no significant bias from the selection of patients or inaccuracy in reporting outcomes. CONCLUSIONS: This large unselected group of primary rhegmatogenous retinal detachments provides a representative sample for considering variations in re-attachment rates.