title: Correlation between visual function and refractive, topographic, pachymetric and aberrometric data in eyes with keratoconus.
abstract: OBJECTIVE
  To analyze the relationship between two visual functions and refractive, topographic, pachymetric and aberrometric indicators in eyes with keratoconus.
  
  
  METHODS
  Corrected distance visual acuity (CDVA), and letter contrast sensitivity (CS) were correlated with refraction, corneal topography, pachymetry, and total corneal wavefront data prospectively in 71 eyes with keratoconus. The topographic indices assessed were simulated keratometry for the flattest and steepest meridians (SimK1 and SimK2), posterior steeper K (Ks), elevation value in best-fit sphere (BFS) maps, squared eccentricity (Є(2)), aspheric asymmetric index (AAI), pachymetry, thickness progression index (TPI), the amount of pachymetric decentralization (APD), and GalileiTM-keratoconus indices.
  
  
  RESULTS
  The mean CDVA (expressed as logMAR) were 0.25±0.21. The mean CS was 1.25±0.46. The spherical refraction correlated well with CDVA (r=-0.526, P<0.001). From topographic indices, SRI correlated with CS (r=-0.695), and IAI with CS (r=-0.672) (P<0.001 for all). Root mean square (RMS) was 4.3±1.81 µm, spherical aberration (SA) was -0.4±0.67 µm, vertical and horizontal coma were -2.1±1.47 and -0.4±0.72 µm. All wavefront data (except horizontal coma), AAI, Є(2) and maximum BFS correlated significantly with the visual function (P≤0.001 for all).
  
  
  CONCLUSIONS
  In this study, CS is more affected than CDVA as a visual function. The quantity and quality of vision is significantly correlated with well-known and new topographic indices. There is not a significant correlation between visual function and pachymetric parameters. The significantly correlated indices can be used in staging keratoconus and to follow the outcome of a treatment.
authors: Department of Ophthalmology, Ankara Numune Education and Research Hospital, Ankara 06170, Turkey.
authors: Neslihan
authors: N
authors: Bayraktar Bilen
authors: Department of Ophthalmology, Gazi University Medical School, Ankara 06500, Turkey.
authors: Ibrahim F
authors: IF
authors: Hepsen
authors: Ocular Bioengineering & Refractive Surgery Sectors, Institute of Vision, Department of Ophthalmology, Paulista School of Medicine, Federal University of São Paulo, São Paulo 05508-060, Brazil.
authors: Carlos G
authors: CG
authors: Arce
keywords: contrast sensitivity; corneal aberration; keratoconus; topographic index; visual quality