title: Effect of 3rd-order aberrations on human vision.
abstract: OBJECTIVE
  To investigate the effect of 3rd-order aberrations on human vision.
  
  
  METHODS
  Grupo de Ciencias de la Visión, University of Murcia, Murcia, Spain.
  
  
  METHODS
  The 3rd-order aberrations coma and trefoil were induced with purpose-designed soft contact lenses, 3 inducing coma (low [0.05 microm], medium [0.13 microm], high [1.03 microm]) and 3 inducing trefoil (low [0.07 microm], medium [0.17 microm], high [0.96 microm]). Monocular high-contrast (HCVA) and low-contrast (LCVA) visual acuities and contrast sensitivity were measured in 11 subjects wearing contact lenses with a 5.0 mm artificial pupil.
  
  
  RESULTS
  The reduction in HCVA and LCVA was statistically significant only for the highest coma and trefoil values (P<.0001). For coma, the mean change in HCVA was 0.193 logMAR +/- 0.100 (SD) and in LCVA, 0.386 +/- 0.136 logMAR. For trefoil, it was 0.204 +/- 0.128 logMAR and 0.395 +/- 0.141 logMAR, respectively. No differences were found for the lower degrees (P>.2). Contrast sensitivity was significantly reduced with the highest coma and trefoil values (P<.0001) (mean change 0.390 +/- 0.157 and 0.404 +/- 0.135, respectively). Lower degrees did not cause significant changes in contrast sensitivity (P>.1). The effect of induced coma and trefoil on HCVA, LCVA, and contrast sensitivity was similar at each level of induced aberration (P>.01).
  
  
  CONCLUSIONS
  Large values of coma and trefoil (approximately 1 mum) significantly reduced visual performance. Only patients with high 3rd-order aberrations, such as those that occur in refractive surgery or in cases of distorted optics, would benefit from this correction.
authors.affiliation: Vision Science Group, Institute on Aging, University of Murcia, Murcia, Spain.
authors.forename: Vicente
authors.initials: V
authors.lastname: Fernández-Sánchez
authors.forename: M Eugenia
authors.initials: ME
authors.lastname: Ponce
authors.forename: Francisco
authors.initials: F
authors.lastname: Lara
authors.forename: Robert
authors.initials: R
authors.lastname: Montés-Micó
authors.forename: José F
authors.initials: JF
authors.lastname: Castejón-Mochón
authors.forename: Norberto
authors.initials: N
authors.lastname: López-Gil
mesh_terms: D000328:Adult; D003263:Contact Lenses, Hydrophilic / Q000009:adverse effects*; D015350:Contrast Sensitivity / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008954:Models, Biological; D012030:Refractive Errors / Q000209:etiology / Q000503:physiopathology*; D014786:Vision Disorders / Q000209:etiology / Q000503:physiopathology*; D014785:Vision, Ocular / Q000502:physiology; D014792:Visual Acuity / Q000502:physiology*