title: Central corneal thickness and normal tension glaucoma: a cross-sectional study.
abstract: BACKGROUND
  Recently published evidence has identified thinner central corneal thickness (CCT) as a strong predictive factor for the conversion from ocular hypertension (OHT) to primary open-angle glaucoma (POAG). The association between CCT and development of normal-tension glaucoma (NTG), however, is less clear. Accordingly, we designed this cross-sectional study to further explore the relationship between CCT and NTG.
  
  
  METHODS
  All patients with a clinical diagnosis of NTG and NTG suspect (NTGS) who were seen from September 2002 through May 2003 at the Albuquerque VA Medical Center eye clinic were identified retrospectively. After eligible subjects were categorized into no, mild, moderate, and advanced visual field loss groups, analysis of variance (ANOVA) and regression analyses were used to determine group differences for several IOP variables, several systemic variables, and CCT. Additional analyses were completed after eligible subjects were recategorized into thin, intermediate, and thick CCT groups.
  
  
  RESULTS
  Eighty-four eyes in 84 NTGS subjects and 56 eyes in 56 NTG subjects were studied. Mean CCT was significantly thicker in the no field loss group (NTGS) when compared with all 3 groups with glaucomatous visual field loss (NTG). In multivariate regression analysis, the association between CCT and the presence of NTG-related visual field loss was robust and independent. Conversely, no relationship was found between CCT and severity of NTG-related visual field loss.
  
  
  CONCLUSIONS
  In eyes characterized by statistically normal intraocular pressure (IOP) measurements as measured by Goldmann applanation tonometry, we found a significant relationship between CCT and the presence, but not severity, of glaucomatous visual field loss. A prospective study is required to further explore and confirm these relationships.
authors.affiliation: Albuquerque VA Medical Center, Albuquerque, New Mexico 87108, USA. Michael.sullivan-mee@med.va.gov
authors.forename: Michael
authors.initials: M
authors.lastname: Sullivan-Mee
authors.forename: Kathy D
authors.initials: KD
authors.lastname: Halverson
authors.forename: Mollie C
authors.initials: MC
authors.lastname: Saxon
authors.forename: Glenn B
authors.initials: GB
authors.lastname: Saxon
authors.forename: Clifford
authors.initials: C
authors.lastname: Qualls
mesh_terms: D000368:Aged; D003315:Cornea / Q000000981:diagnostic imaging*; D003430:Cross-Sectional Studies; D005902:Glaucoma, Open-Angle / Q000000981:diagnostic imaging* / Q000503:physiopathology; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology; D008875:Middle Aged; D011379:Prognosis; D012189:Retrospective Studies; D012720:Severity of Illness Index; D014463:Ultrasonography; D014794:Visual Fields