title: In-vivo corneal biomechanical analysis of unilateral keratoconus.
abstract: OBJECTIVE
  To evaluate and compare corneal biomechanical findings measured by ocular response analyzer, topographic and pachymetric findings in patients with unilateral keratoconus patients and healthy controls.
  
  
  METHODS
  This is an observational, case-control study. Patients with keratoconus in one eye and forme fruste keratoconus in the fellow eye were compared with sex and age matched with controls healthy subjects. All subjects were evaluated with rotating scheimpflug imaging system. The receiver-operating-characteristic curves were analyzed to evaluate the sensitivity and specificity of the parameters.
  
  
  RESULTS
  Twenty-seven patients with keratoconus in one eye and forme fruste keratoconus in the fellow eye were compared with 40 eyes of 40 normal subjects. Corneal hysteresis (CH) was 8.0±1.7 mm Hg in keratoconus group, 8.3±1.6 mm Hg in forme fruste keratoconus group, and 9.8±1.6 mm Hg in control groups (P=0.54 between keratoconus and forme fruste keratoconus groups, P<0.01 between control group and other groups). Corneal resistance factor (CRF) was 7.1±2.2 mm Hg in keratoconus group, 7.8±1.2 mm Hg in forme fruste keratoconus group and 9.9±1.5 mm Hg in control group (P<0.001 between control group and other groups). Using receiver-operating-characteristic analysis, the area under curve values of the parameters to distinguish forme fruste keratoconus from control subjects were: CH (0.768), CRF (0.866). Best cut-off points were 9.3 mm Hg and 8.8 mm Hg for CH and CRF respectively.
  
  
  CONCLUSIONS
  Ocular response analyzer parameters (CH and CRF) are found to be significantly lower in forme fruste keratoconus patients compared to normal control subjects.
authors.affiliation: Department of Ophthalmology, Bulent Ecevit University, Kozlu 67600, Zonguldak, Turkey.
authors.forename: Orhan
authors.initials: O
authors.lastname: Ayar
authors.affiliation: Department of Ophthalmology, Gazi University, Ankara 06500, Turkey.
authors.forename: Mehmet Cuneyt
authors.initials: MC
authors.lastname: Ozmen
authors.affiliation: Department of Ophthalmology, Medipol University, Istanbul 34214, Turkey.
authors.forename: Orkun
authors.initials: O
authors.lastname: Muftuoglu
authors.affiliation: Department of Ophthalmology, Bulent Ecevit University, Kozlu 67600, Zonguldak, Turkey.
authors.forename: Mehmet Orcun
authors.initials: MO
authors.lastname: Akdemir
authors.affiliation: Ulucanlar Eye Research and Education Hospital, Ankara 06340, Turkey.
authors.forename: Mustafa
authors.initials: M
authors.lastname: Koc
authors.affiliation: Kudret Eye Hospital, Ankara 06700, Turkey.
authors.forename: Kemal
authors.initials: K
authors.lastname: Ozulken
keywords: forme fruste keratoconus; keratoconus; ocular response analyzer