Abstract
Abstract: :
Purpose: To assess risk factors for contact lens (CL) related microbial keratitis (MK). Methods: A 2 year case–control study commenced in December 2003. Cases are CL wearers attending as new patients to Moorfields Eye Hospital (MEH) Accident and Emergency (A&E) with proven or presumed MK. There are two groups of controls: Hospital Controls (H–Cs) and Population–based Controls (POP–Cs). H–Cs are CL wearers attending A&E as new patients with a disorder unrelated to CL wear, and POP–Cs are CL wearers randomly selected from the MEH A&E catchment area who have never attended MEH. Persons with a medical indication for CL wear are excluded. Hospital patients complete a self–administered questionnaire, while POP–Cs are interviewed by telephone. Results: After 10 months there were 82 cases, 235 H–Cs and 255 POP–Cs wearing daily disposable, planned replacement or silicone hydrogel CL. Interim multiple logistic regression analysis was initially carried out using H–Cs and POP–Cs separately, but since the main findings were similar, analysis was repeated with controls combined. Significant risk factors were overnight wear (consistent for all three CL types), with an odds ratio (OR) of 5.22 (95% confidence limits 2.27 – 12.02, p < 0.001); full–time rather than part–time wear (OR: 4.51, 1.29 – 15.75, p = 0.018); male gender (OR: 2.59, 1.52 – 4.41, p < 0.001) and failure to wash hands prior to CL handling (OR: 2.00, 1.17 – 3.42, p = 0.011). Conclusions: This interim analysis suggests that, irrespective of CL type, overnight wear continues to be an important risk factor for CL related MK.
Keywords: clinical (human) or epidemiologic studies: risk factor assessment • contact lens • keratitis