title: Correlations between corneal and optic nerve head variables in healthy subjects and patients with primary open angle glaucoma.
abstract: OBJECTIVE
  To correlate corneal variables (determined using the Pentacam) with optic nerve head (ONH) variables determined using the Heidelberg retina tomograph (HRT) in healthy subjects and patients diagnosed with primary open angle glaucoma (POAG).
  
  
  METHODS
  Measurements were made in 75 healthy eyes and 73 eyes with POAG and correlations examined through Pearson correlation coefficients between the two sets of variables in the two subject groups. The corneal variables determined were corneal volume (CVol), central corneal thickness (CCT), overall corneal thickness (OvCT), the mean thickness of a circular zone centered at the corneal apex of 1 mm radius (zone I) and the mean thickness of several concentric rings, also centered at the apex until the limbus, each of 1 mm width (zones II to VI respectively). The ONH variables were determined using the HRT.
  
  
  RESULTS
  The following pairs of variables were correlated in the control group: CCT-disc area (DAr) (-0.48; P<0.0001), Zone I-DAr (-0.503; P<0.0001) and Zone II-DAr (-0.443; P<0.0001); and in the POAG group: CCT-cup-to-disc area ratio (CDRa) (-0.402; P<0.0001), Zone I-CDRa (-0.418; P<0.0001), Zone II-CDRa (-0.405; P=0.006), Zone I-cup shape measure (CSM) (-0.415; P=0.002), Zone II-CSM (-0.405; P=0.001), Zone IV-height variation contour (HVC) (0.378; P=0.002); Zone V-HVC (0.388, P<0.0001).
  
  
  CONCLUSIONS
  In the healthy subjects, significant negative correlation was detected between central and paracentral corneal thickness and optic disc area. In contrast, the POAG patients showed significant negative correlation between central and paracentral corneal thickness and the cup-disc ratio and CSM, and positive correlation between peripheral corneal thickness and HVC.
authors.affiliation: Department of Ophthalmology, Clinico San Carlos Hospital, Complutense University of Madrid, Madrid 28040, Spain.
authors.forename: Federico
authors.initials: F
authors.lastname: Saenz-Frances
authors.affiliation: Technology of Knowledge Institute, Complutense University of Madrid, Madrid 28223, Spain.
authors.forename: Luis
authors.initials: L
authors.lastname: Jañez
authors.affiliation: Department of Ophthalmology, Clinico San Carlos Hospital, Complutense University of Madrid, Madrid 28040, Spain.
authors.forename: Lara
authors.initials: L
authors.lastname: Borrego-Sanz
authors.affiliation: Department of Ophthalmology, Clinico San Carlos Hospital, Complutense University of Madrid, Madrid 28040, Spain.
authors.forename: Clara
authors.initials: C
authors.lastname: Berrozpe-Villabona
authors.affiliation: Department of Ophthalmology, Clinico San Carlos Hospital, Complutense University of Madrid, Madrid 28040, Spain.
authors.forename: Jose Maria
authors.initials: JM
authors.lastname: Martinez-de-la-Casa
authors.affiliation: Department of Ophthalmology, Clinico San Carlos Hospital, Complutense University of Madrid, Madrid 28040, Spain.
authors.forename: Laura
authors.initials: L
authors.lastname: Morales-Fernandez
authors.affiliation: Department of Ophthalmology, Clinico San Carlos Hospital, Complutense University of Madrid, Madrid 28040, Spain.
authors.forename: Julian
authors.initials: J
authors.lastname: Garcia-Sanchez
authors.affiliation: Department of Ophthalmology, Clinico San Carlos Hospital, Complutense University of Madrid, Madrid 28040, Spain.
authors.forename: Enrique
authors.initials: E
authors.lastname: Santos-Bueso
authors.affiliation: Department of Ophthalmology, Clinico San Carlos Hospital, Complutense University of Madrid, Madrid 28040, Spain.
authors.forename: Julian
authors.initials: J
authors.lastname: Garcia-Feijoo
keywords: corneal thickness; glaucoma; optic nerve head