title: Repeatability of topographic and aberrometric measurements at different accommodative states using a combined topographer and open-view aberrometer.
abstract: OBJECTIVE
  To evaluate the repeatability of corneal first-surface aberrations and aberrometric measurements of a combined aberrometer-topographer (iTrace Visual Function Analyzer) for 5 accommodative stimuli.
  
  
  METHODS
  Department of Ophthalmology, Goethe-University, Frankfurt, Germany.
  
  
  METHODS
  Prospective case series.
  
  
  METHODS
  Eyes of young adults with low to moderate myopia or hyperopia were examined in 2 measurement series comprising 3 corneal topography measurements and wavefront measurements focusing on targets at 5 distances (0.4, 0.5, 0.6, 1.0, and 4.0 m). Repeatability was analyzed using the standard deviation (SD) within 6 measurements and the coefficient of repeatability (CoR) by Bland-Altman analysis of the means of the 2 measurement series.
  
  
  RESULTS
  Fifty eyes (50 subjects) were evaluated. The lowest calculated mean SD/CoR measurements using the aberrometer function at 5 target distances were 0.07 μm/0.14 μm for total ocular aberrations root mean square (RMS), 0.07 μm/0.16 μm for lower-order aberrations (LOAs) RMS, 0.03 μm/0.66 μm for higher-order aberrations (HOAs) RMS, 0.10 diopter (D)/0.22 D for sphere, 0.08 D/0.13 D for cylinder, and 0.09 D/0.21 D for the spherical equivalent (SE). Repeatability of the total RMS, LOAs RMS, sphere, and SE measurements improved with increasing target distance (P < .01 for aberrometric values; P < .03 for refractive values). Measurement reproducibility using the corneal topographer showed mean SDs/CoRs of 0.19 μm/0.41 μm for total RMS, 0.19 μm/0.39 μm for LOAs RMS, and 0.08 μm/0.23 μm for HOAs RMS.
  
  
  CONCLUSIONS
  The aberrometer showed satisfactory results for measurement repeatability at all target distances and declining repeatability with increasing accommodation effort.
  
  
  BACKGROUND
  No author has a financial or proprietary interest in any material or method mentioned.
authors.affiliation: From the Department of Ophthalmology, Goethe-University, Frankfurt, Germany.
authors.forename: Claudia
authors.initials: C
authors.lastname: Gabriel
authors.affiliation: From the Department of Ophthalmology, Goethe-University, Frankfurt, Germany.
authors.forename: Oliver Klaus
authors.initials: OK
authors.lastname: Klaproth
authors.affiliation: From the Department of Ophthalmology, Goethe-University, Frankfurt, Germany.
authors.forename: Christine
authors.initials: C
authors.lastname: Titke
authors.affiliation: From the Department of Ophthalmology, Goethe-University, Frankfurt, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Baumeister
authors.affiliation: From the Department of Ophthalmology, Goethe-University, Frankfurt, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Bühren
authors.affiliation: From the Department of Ophthalmology, Goethe-University, Frankfurt, Germany. Electronic address: kohnen@em.uni-frankfurt.de.
authors.forename: Thomas
authors.initials: T
authors.lastname: Kohnen
mesh_terms: D057128:Aberrometry; D000065:Accommodation, Ocular / Q000502:physiology*; D000328:Adult; D003315:Cornea / Q000503:physiopathology*; D019781:Corneal Topography; D057108:Corneal Wavefront Aberration / Q000503:physiopathology*; D005260:Female; D006801:Humans; D006956:Hyperopia / Q000503:physiopathology*; D008297:Male; D009216:Myopia / Q000503:physiopathology*; D011446:Prospective Studies; D015203:Reproducibility of Results; D055815:Young Adult