title: Normal-eye Zernike coefficients and root-mean-square wavefront errors.
abstract: OBJECTIVE
  To compare aberrometry measurements from multiple sites and compute mean Zernike coefficients and root-mean-square (RMS) values for the entire data pool to serve as a reference set for normal, healthy adult eyes.
  
  
  METHODS
  Northeastern State University, Tahlequah, Oklahoma, USA.
  
  
  METHODS
  Data were collected from 10 laboratories that measured higher-order aberrations (HOAs) in normal, healthy adult eyes using Shack-Hartmann aberrometry (2560 eyes of 1433 subjects). Signed Zernike coefficients were scaled to pupil diameters of 6.0 mm, 5.0 mm, 4.0 mm, and 3.0 mm and corrected to a common wavelength of 550 nm. The mean signed and absolute Zernike coefficients across data sets were compared. Then, the following were computed: overall mean values for signed and absolute Zernike coefficients; polar Zernike magnitudes and RMS values for coma-like aberrations (Z(3)(+/-1) and Z(5)(+/-1) combined); spherical-like aberrations (Z(4)(0) and Z(6)(0) combined); and 3rd-, 4th-, 5th-, and 6th-order, and higher-order aberrations (orders 3 to 6).
  
  
  RESULTS
  The different data sets showed good agreement for Zernike coefficients values across most higher-order modes, with greater variability for Z(4)(0) and Z(3)(-1). The most prominent modes and their mean absolute values (6.0-mm pupil) were, respectively, Z(3)(-1) and 0.14 microm, Z(4)(0) and 0.13 microm, and Z(3)(-3) and 0.11 microm. The mean total higher-order RMS was 0.33 microm.
  
  
  CONCLUSIONS
  There was a general consensus for the magnitude of HOAs expected in normal adult human eyes. At least 90% of the sample had aberrations less than double the mean values reported here. These values can serve as a set of reference norms.
authors.affiliation: Northeastern State University, Tahlequah, Oklahoma, USA. salmonto@nsuok.edu
authors.forename: Thomas O
authors.initials: TO
authors.lastname: Salmon
authors.forename: Corina
authors.initials: C
authors.lastname: van de Pol
mesh_terms: D000328:Adult; D003315:Cornea / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D012016:Reference Values; D012029:Refraction, Ocular; D012030:Refractive Errors / Q000175:diagnosis*; D016008:Statistical Distributions