title: The effect of optical blur on central and peripheral word visual acuity.
abstract: OBJECTIVE
  We investigated how dioptric blur affected word acuity thresholds for targets presented at different retinal eccentricities.
  
  
  METHODS
  Word thresholds were measured at 0, 5, and 10 degrees and for different Weber contrast levels of 4, 10, 45, and 90%.
  
  
  RESULTS
  We find that increasing optical blur increased word acuity thresholds, but the extent of change was dependent on retinal eccentricity and stimulus contrast. In particular, the resolution reduction per diopter of blur (as indicated by the slope of lines fitted to data) was significantly less at peripheral locations (0 degrees vs. 5 and 10 degrees) and for low-contrast targets.
  
  
  CONCLUSIONS
  These findings provide useful guidelines to predict how patients with contrast loss and/or those that rely upon an eccentric retinal location for reading respond to the introduction of optical blur in a clinical setting.
authors.affiliation: *PhD †BOptom ‡BSc(Optom), PhD The School of Optometry and Vision Science (SKK, MK), The University of New South Wales, Kensington, New South Wales, Australia; Department of Optometry and Vision Science (PHC, JO, MK), University of Auckland, Auckland New Zealand; and Centre for Eye Health (MK), The University of New South Wales, Kensington, New South Wales, Australia.
authors.forename: Sieu K
authors.initials: SK
authors.lastname: Khuu
authors.forename: Philip Hi
authors.initials: PH
authors.lastname: Chou
authors.forename: Jacob
authors.initials: J
authors.lastname: Ormsby
authors.forename: Michael
authors.initials: M
authors.lastname: Kalloniatis
mesh_terms: D005260:Female; D006801:Humans; D008297:Male; D011932:Reading; D012029:Refraction, Ocular / Q000502:physiology; D012030:Refractive Errors / Q000503:physiopathology*; D012684:Sensory Thresholds; D014785:Vision, Ocular / Q000502:physiology; D014792:Visual Acuity / Q000502:physiology*; D055815:Young Adult