title: Risk factors for nonulcerative contact lens complications in an ophthalmic accident and emergency department: a case-control study.
abstract: OBJECTIVE
  To assess the relative risks of acute, nonulcerative complications with recently introduced contact lens (CL) wear modalities (compared with the previously most common soft lens wear schedule), and to identify any other associated factors.
  
  
  METHODS
  A 2-year prospective case-control study commencing in December 2003.
  
  
  METHODS
  Cases were 877 CL wearers attending Moorfields Eye Hospital with CL-related disorders other than microbial keratitis. Controls were 1069 hospital controls who were CL wearers presenting with a disorder unrelated to CL wear, and 639 population-based controls who were CL wearers randomly selected from the Moorfields catchment area. Hospital patients completed a self-administered questionnaire; population controls were interviewed by telephone.
  
  
  METHODS
  The relative risks of developing the CL-related disorders with different CL types were evaluated. For the more common disorders, multivariable analysis was undertaken.
  
  
  METHODS
  The relative risk of developing an acute, nonulcerative, CL-related disorder.
  
  
  RESULTS
  Compared with planned replacement soft CL, daily disposable lenses significantly reduced the risk of toxic/hypersensitivity (odds ratios for CL solution disorders and papillary conjunctivitis 0.1 and 0.5; P<0.001 and P = 0.05, respectively) and metabolic disorders (0.4; P=0.04), but the most commonly used brand was associated with increased risks of sterile keratitis (2.7x; 95% confidence interval [CI], 1.7-4.1; P<0.001), mechanical disorders (2.2x; 95% CI, 1.5-3.2; P<0.001), and a tendency for patients to have lens removal difficulties (P<0.001). Silicone hydrogel CL wear was free from hypoxic complications but associated with an increased risk of sterile keratitis (2.0x; 95% CI, 1.2-3.3; P=0.005), mechanical disorders (1.8x; 95% CI, 1.1-2.8; P=0.015), and attendance with any nonulcerative complication (1.9x; 95% CI, 1.5-2.6; P<0.001) when compared with other reusable soft lenses. Significant additional risk factors were identified for sterile keratitis (overnight wear [ON], more days per week of lens wear, poor hand hygiene, smoking, and less CL experience) and mechanical disorders (ON and less CL experience).
  
  
  CONCLUSIONS
  Neither of the 2 recently introduced CL modalities-daily disposable and silicone hydrogel lenses-reduced the overall risk of acute nonulcerative disorders.
authors.affiliation: Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom. cherry.radford@moorfields.nhs.uk
authors.forename: Cherry F
authors.initials: CF
authors.lastname: Radford
authors.forename: Darwin
authors.initials: D
authors.lastname: Minassian
authors.forename: John K G
authors.initials: JK
authors.lastname: Dart
authors.forename: Fiona
authors.initials: F
authors.lastname: Stapleton
authors.forename: Seema
authors.initials: S
authors.lastname: Verma
mesh_terms: D000059:Accidents; D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D003229:Conjunctival Diseases / Q000209:etiology*; D003261:Contact Lenses / Q000009:adverse effects*; D003316:Corneal Diseases / Q000209:etiology*; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D005141:Eyelid Diseases / Q000209:etiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009885:Ophthalmology / Q000706:statistics & numerical data*; D011446:Prospective Studies; D012307:Risk Factors; D011795:Surveys and Questionnaires