title: Comparing corneal variables in healthy subjects and patients with primary open-angle glaucoma.
abstract: OBJECTIVE
  This study was designed to identify possible differences between healthy subjects and patients with primary open-angle glaucoma (POAG) in keratometry, central corneal thickness, overall corneal thickness, mean thickness of a circular zone centered at the corneal apex of 1-mm radius (zone I), and mean thickness of several concentric rings also centered at the apex of 1-mm width (zones II to VI, respectively).
  
  
  METHODS
  These variables were recorded in 126 healthy subjects and 130 patients with POAG. Corneal thicknesses and the power of the flattest and steepest axes were compared between the two populations using a t-test and the position of the flattest axis using a Mann-Whitney U test. A binary logistic regression procedure was used to determine the diagnostic capacity of the corneal variables using the area under the receiver operator characteristic curve (AUC) to select the best regression equation.
  
  
  RESULTS
  Significant differences between subjects and patients were detected in mean corneal thickness and in mean thicknesses of zones I to VI. The logistic regression model included as predictors the mean corneal thickness and the mean thicknesses of zones IV and VI; for this model, the AUC was 0.711, sensitivity was 67.7%, and specificity was 65.5%.
  
  
  CONCLUSIONS
  Healthy subjects and glaucoma patients differ significantly in terms of mean overall corneal thickness and thicknesses of the corneal zones I to VI defined here. The variables mean corneal thickness and mean thicknesses of zones IV and VI are able to discriminate between subjects with or without glaucoma.
authors.affiliation: Department of Ophthalmology, Hospital Clínico San Carlos, Madrid, Spain. federicosaenzfrancessb@gmail.com
authors.forename: Federico
authors.initials: F
authors.lastname: Saenz-Frances
authors.forename: Julian
authors.initials: J
authors.lastname: Garcia-Feijó
authors.forename: Luis
authors.initials: L
authors.lastname: Jañez
authors.forename: Lara
authors.initials: L
authors.lastname: Borrego-Sanz
authors.forename: Jose M
authors.initials: JM
authors.lastname: Martinez de la Casa
authors.forename: Ana
authors.initials: A
authors.lastname: Fernandez-Vidal
authors.forename: Carmen
authors.initials: C
authors.lastname: Mendez-Hernández
authors.forename: Enrique
authors.initials: E
authors.lastname: Santos-Bueso
authors.forename: Juan
authors.initials: J
authors.lastname: Reche-Frutos
authors.forename: Julian
authors.initials: J
authors.lastname: Garcia-Sánchez
mesh_terms: D000886:Anthropometry; D019540:Area Under Curve; D003315:Cornea / Q000000981:diagnostic imaging / Q000473:pathology*; D003430:Cross-Sectional Studies; D005902:Glaucoma, Open-Angle / Q000175:diagnosis*; D006068:Gonioscopy; D006801:Humans; D012372:ROC Curve; D014463:Ultrasonography; D014794:Visual Fields