title: Higher-order wavefront aberration and letter-contrast sensitivity in keratoconus.
abstract: OBJECTIVE
  To evaluate the relation between higher-order aberration of the eye and contrast sensitivity function in eyes with keratoconus.
  
  
  METHODS
  In 22 eyes of 14 patients with keratoconus (age 30.5+/-8.4 years, means+/-SD) and 26 eyes of 13 normal controls (age 29.2+/-6.7 years), ocular higher-order wavefront aberration for a 6-mm pupil was measured with the Hartmann-Schack aberrometer (KR-9000 PW, Topcon). The root mean square (RMS) of third- and fourth-order Zernike coefficients was used to represent higher-order aberrations. The letter-contrast sensitivity was examined using the CSV-1000LV contrast chart (Vector Vision).
  
  
  RESULTS
  In the keratoconus group, the letter-contrast sensitivity showed significant correlation with third-order (Spearman's correlation coefficient r=-0.736, P<0.001) and fourth-order aberrations (r=-0.464, P<0.05). There was borderline correlation between log MAR BSCVA and third-order (r=0.413, P=0.070) and fourth-order aberrations (r=0.394, P=0.086). In the normal group, the letter-contrast sensitivity had no significant correlation with third-order (r=-0.170, P=0.411) and fourth-order aberrations (r=-0.088, P=0.673), and log MAR best spectacle-corrected visual acuity (BSCVA) showed no correlation with third-order (r=0.063, P=0.762) and fourth-order aberrations (r=-0.282, P=0.165).
  
  
  CONCLUSIONS
  In eyes with keratoconus, there is significant correlation between contrast sensitivity and ocular higher-order wavefront aberrations.
authors.affiliation: Department of Ophthalmology, Institute of Clinical Medicine, University of Tsukuba, Ibaraki, Japan.
authors.forename: C
authors.initials: C
authors.lastname: Okamoto
authors.forename: F
authors.initials: F
authors.lastname: Okamoto
authors.forename: T
authors.initials: T
authors.lastname: Samejima
authors.forename: K
authors.initials: K
authors.lastname: Miyata
authors.forename: T
authors.initials: T
authors.lastname: Oshika
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D015350:Contrast Sensitivity / Q000502:physiology*; D005260:Female; D006801:Humans; D007640:Keratoconus / Q000503:physiopathology*; D008297:Male; D012030:Refractive Errors / Q000503:physiopathology*; D014786:Vision Disorders / Q000503:physiopathology*