title: Visual acuity in contact lens wearers.
abstract: OBJECTIVE
  The difference between high- and low-contrast visual acuity provides a sensitive indicator of vision loss in ocular disease; however, the effect of refractive error correction on this difference is still debated.
  
  
  METHODS
  High- and low-contrast visual acuity was measured in 116 rigid gas permeable contact lens wearers, 51 spectacle wearers, and 50 soft contact lens wearers with habitual and best correction. Twenty-nine of the soft contact lens wearers reported that they wore disposable contact lenses (discarded on a monthly or more frequent basis), whereas the other 21 soft contact lens wearers wore traditional soft contact lenses.
  
  
  RESULTS
  Rigid gas permeable contact lens wearers had statistically worse high-contrast habitual visual acuity than spectacle wearers (Tukey-Kramer, p = 0.0075). Traditional soft contact lens wearers had significantly worse low-contrast visual acuity compared with all other groups (Tukey-Kramer, p < 0.02 for each comparison). Traditional soft contact lens wearers had a significantly larger difference between high- and low-contrast visual acuity with best correction compared with rigid gas permeable wearers (Tukey-Kramer, p = 0.0099).
  
  
  CONCLUSIONS
  Rigid gas permeable contact lens wearers had statistically worse habitual high-contrast visual acuity compared with spectacle wearers, but no difference was present under best-corrected conditions. We hypothesize that rigid gas permeable contact lens wearers were not wearing their optimal correction habitually. Traditional soft contact lens wearers had significantly worse low-contrast visual acuity. They also had a larger difference between their best-corrected high- and low-contrast visual acuity scores compared with rigid gas permeable contact lens wearers.
authors.affiliation: The Ohio State University College of Optometry, Columbus 43210-1240, USA. mbailey@optometry.ohio-state.edu
authors.forename: M D
authors.initials: MD
authors.lastname: Bailey
authors.forename: J J
authors.initials: JJ
authors.lastname: Walline
authors.forename: G L
authors.initials: GL
authors.lastname: Mitchell
authors.forename: K
authors.initials: K
authors.lastname: Zadnik
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D003261:Contact Lenses; D004209:Disposable Equipment; D005139:Eyeglasses; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012030:Refractive Errors / Q000503:physiopathology* / Q000628:therapy*; D014792:Visual Acuity / Q000502:physiology*