title: Effects of optical blur reduction on equivalent intrinsic blur.
abstract: OBJECTIVE
  To determine the effect of optical blur reduction on equivalent intrinsic blur, an estimate of the blur within the visual system, by comparing optical and equivalent intrinsic blur before and after adaptive optics (AO) correction of wavefront error.
  
  
  METHODS
  Twelve visually normal subjects (mean [±SD] age, 31 [±12] years) participated in this study. Equivalent intrinsic blur (σint) was derived using a previously described model. Optical blur (σopt) caused by high-order aberrations was quantified by Shack-Hartmann aberrometry and minimized using AO correction of wavefront error.
  
  
  RESULTS
  σopt and σint were significantly reduced and visual acuity was significantly improved after AO correction (p ≤ 0.004). Reductions in σopt and σint were linearly dependent on the values before AO correction (r ≥ 0.94, p ≤ 0.002). The reduction in σint was greater than the reduction in σopt, although it was marginally significant (p = 0.05). σint after AO correlated significantly with σint before AO (r = 0.92, p < 0.001), and the two parameters were related linearly with a slope of 0.46.
  
  
  CONCLUSIONS
  Reduction in equivalent intrinsic blur was greater than the reduction in optical blur after AO correction of wavefront error. This finding implies that visual acuity in subjects with high equivalent intrinsic blur can be improved beyond that expected from the reduction in optical blur alone.
authors.affiliation: *MD, MPH †MS ‡PhD Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, Illinois (all authors).
authors.forename: Ali
authors.initials: A
authors.lastname: Kord Valeshabad
authors.forename: Justin
authors.initials: J
authors.lastname: Wanek
authors.forename: J Jason
authors.initials: JJ
authors.lastname: McAnany
authors.forename: Mahnaz
authors.initials: M
authors.lastname: Shahidi
mesh_terms: D057128:Aberrometry; D000293:Adolescent; D000328:Adult; D057108:Corneal Wavefront Aberration / Q000503:physiopathology / Q000628:therapy*; D005139:Eyeglasses; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012029:Refraction, Ocular / Q000502:physiology; D014786:Vision Disorders / Q000503:physiopathology / Q000628:therapy*; D014792:Visual Acuity / Q000502:physiology*; D055815:Young Adult