title: The influence of soft contact lens wear and two weeks cessation of lens wear on corneal curvature.
abstract: BACKGROUND
  Accurate corneal measurements are crucial in corneal refractive surgery (CRS) to ensure successful outcomes. Soft contact lens (SCL) wear may result in changes to corneal curvature and structure. United States Food and Drug Administration (FDA) pre-operative guidelines recommend that prior to CRS, SCL wearers cease SCL wear for "at least two weeks before examination and treatment" [1]. Corneal curvature changes induced by SCL wear may take longer than two weeks to resolve.
  
  
  OBJECTIVE
  To examine the effect of SCL wear on corneal curvature before and following two weeks SCL wear cessation. To explore the possible impact of different SCL materials and years of SCL wear.
  
  
  METHODS
  Retrospective data analysis, between a group of SCL wearers (SCL: n=45); and a non-contact lens control group (NCL: n=45). Corneal curvature parameters were measured using the Pentacam (Oculus, Germany), before and following two weeks cessation of SCL wear.
  
  
  RESULTS
  No significant differences in keratometry or Sagittal radius of curvature between SCL and NCL groups prior to or following SCL cessation. Tangential radius of curvature showed significant inferior steepening for the SCL group prior to SCL cessation (SCL vs. NCL; 7.77±0.30mm vs. 7.90±0.30mm; p=0.04). Following two weeks cessation of SCL wear this appeared to have resolved.
  
  
  CONCLUSIONS
  Two weeks cessation of SCL wear appears sufficient for resolution of corneal curvature changes with modern SCL materials and years of SCL wear. However, further studies with longer lens deprivation periods are required to ensure stability for all SCL wearing patients.
authors: Dublin Institute of Technology, Ireland. Electronic address: aoifemarie.lloyd@dit.ie.
authors: Aoife
authors: A
authors: Lloyd McKernan
authors: Dublin Institute of Technology, Ireland. Electronic address: Veronica.Odwyer@dit.ie.
authors: Veronica
authors: V
authors: O'Dwyer
authors: Plymouth University, United Kingdom. Electronic address: luisa.simo@plymouth.ac.uk.
authors: Luisa
authors: L
authors: Simo Mannion
mesh_terms: D000328:Adult; D003263:Contact Lenses, Hydrophilic; D003315:Cornea / Q000033:anatomy & histology*; D063171:Corneal Pachymetry; D005260:Female; D006801:Humans; D008297:Male; D012189:Retrospective Studies; D013997:Time Factors; D014054:Tomography; D028761:Withholding Treatment
keywords: Cornea; Pentacam; Soft contact lens; Topography