title: Corneal densitometry and its correlation with age, pachymetry, corneal curvature, and refraction.
abstract: OBJECTIVE
  To determine normative corneal densitometry values in relation to age, sex, refractive error, corneal thickness, and keratometry, measured using the Oculus Pentacam system.
  
  
  METHODS
  Three hundred and thirty-eight healthy subjects (185 men; 153 women) with no corneal disease underwent an exhaustive ocular examination. Corneal densitometry was expressed in standardized grayscale units (GSU).
  
  
  RESULTS
  The mean corneal densitometry over the total area was 16.46 ± 1.85 GSU. The Pearson correlation coefficient for total densitometry was r = 0.542 (p < 0.001). Statistically significant differences were found between men and women for the total area (p = 0.006), with readings of 16.22 ± 1.54 GSU and 16.60 ± 1.83 GSU, respectively. When the cornea was divided into layers of different depths, a significant correlation was found for all layers and age: r = 0.447 (p < 0.001), r = 0.563 (p < 0.001), and r = 0.520 (p < 0.001) for the anterior, central, and posterior layers, respectively. However, when the cornea was divided into concentric annuli starting from the center of the cornea, densitometry was strongly correlated only with age in the 6-10-mm annulus (p < 0.001). Neither mean keratometry nor spherical equivalent was correlated with corneal densitometry in any zone of the cornea (p > 0.05).
  
  
  CONCLUSIONS
  This is the first report of normative corneal densitometry values in relation to keratometry, corneal thickness, and spherical equivalent measured with the latest Oculus Pentacam software. Corneal densitometry increases with age, but corneal keratometry and refractive parameters do not affect light scattering in the human cornea.
authors.affiliation: Innova Ocular, C/Galileo 104, 28003, Madrid, Spain. ngarzon@ioamadrid.com.
authors.forename: Nuria
authors.initials: N
authors.lastname: Garzón
authors.affiliation: Innova Ocular, C/Galileo 104, 28003, Madrid, Spain.
authors.forename: Francisco
authors.initials: F
authors.lastname: Poyales
authors.affiliation: Innova Ocular, C/Galileo 104, 28003, Madrid, Spain.
authors.forename: Igor
authors.initials: I
authors.lastname: Illarramendi
authors.affiliation: Innova Ocular, C/Galileo 104, 28003, Madrid, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Mendicute
authors.affiliation: Innova Ocular, C/Galileo 104, 28003, Madrid, Spain.
authors.forename: Óscar
authors.initials: Ó
authors.lastname: Jáñez
authors.affiliation: Innova Ocular, C/Galileo 104, 28003, Madrid, Spain.
authors.forename: Pedro
authors.initials: P
authors.lastname: Caro
authors.affiliation: Innova Ocular, C/Galileo 104, 28003, Madrid, Spain.
authors.forename: Alfredo
authors.initials: A
authors.lastname: López
authors.affiliation: Innova Ocular, C/Galileo 104, 28003, Madrid, Spain.
authors.forename: Francisco
authors.initials: F
authors.lastname: Argüeso
mesh_terms: D000328:Adult; D000375:Aging / Q000502:physiology*; D003315:Cornea / Q000033:anatomy & histology*; D063171:Corneal Pachymetry; D019781:Corneal Topography; D003720:Densitometry / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012029:Refraction, Ocular / Q000502:physiology*
keywords: Cornea; Corneal densitometry; Corneal transparency