Abstract
Abstract: :
Purpose: To assess risk factors in contact lens (CL) related microbial keratitis. Methods: A 3 month pilot case–control study was undertaken between March and June 2003. Hospital cases and controls were CL wearers attending Moorfields Eye Hospital (MEH) Accident and Emergency (A&E) Department as new patients, cases having a diagnosis of proven or presumed microbial keratitis, and controls attending with a disorder unrelated to CL wear. Population–based controls were CL wearers, randomly selected from the MEH A&E catchment area, who had never previously attended MEH. Persons with a medical indication for CL wear were excluded. Hospital patients completed a self–administered questionnaire, while population controls were interviewed by telephone. Results: There were 20 cases, 74 hospital–based controls (H–Cs) and 183 population–based controls (POP–Cs). Preliminary analysis showed that, among wearers of daily disposable (DD) soft CL, there was an increased risk of microbial keratitis with recent unscheduled overnight use, with an odds ratio (OR) of 21x (1.12 – infinity, p=0.036) using H–Cs, and 8.93x (1.40 – 61.50, p=0.014) using POP–Cs. There was also a suggestion that showering in lenses carried an increased risk, with an OR of 5.1x (0.98 – 28.50, p=0.054) using H–Cs and 3.58x (0.96 – 13.68, p=0.06) using POP–Cs. Conclusions: This feasibility study suggests that microbial keratitis in DD wearers appears to be associated with unscheduled overnight use and hygiene factors. A larger study has commenced in which risk factors will be evaluated in further detail using multivariable analysis.
Keywords: clinical (human) or epidemiologic studies: risk factor assessment • keratitis • contact lens