title: Biomechanical and tomographic analysis of unilateral keratoconus.
abstract: OBJECTIVE
  To evaluate and compare tomographic, clinical, and biomechanical data of patients with unilateral keratoconus and healthy controls.
  
  
  METHODS
  Observational, case-control study. Complete clinical eye examination was followed by topographic (ATLAS), tomographic (Pentacam), and biomechanical (Ocular Response Analyzer) evaluation. Cases were sex- and age-matched with healthy individuals for controls.
  
  
  RESULTS
  Four patients had unilateral keratoconus, and eight healthy patients served as controls. Central corneal thickness was 508±16 μm in the keratoconus group, 531±12.7 μm in the fellow eye group, and 528.6±40.7 μm in the control group (P>.125, all comparisons). Central keratometry was 43.70±2.70 diopters (D) in the keratoconus group, 42.84±1.43 D in the fellow eye group, and 43.81±1.94 D in the control group (P>.45, all comparisons). Corneal astigmatism was 3.30±2.24 D in the keratoconus group, 1.38±1.49 D in the fellow eye group, and 1.34±1.13 D in the control group (P=.037 between the keratoconus and control groups; P=.25 between the keratoconus and fellow eye groups). Corneal hysteresis was 8.13±2 mmHg in the keratoconus group, 8.96±0.86 mmHg in the fellow eye group, and 9.89±1.33 mmHg in the control group (P>.064, all comparisons). Corneal resistance factor was 7.96±2.43 mmHg in the keratoconus group, 8.92±1.39 mmHg in the fellow eye group, and 9.90±2.24 mmHg in the control group (P>.33, all comparisons).
  
  
  CONCLUSIONS
  Corneal hysteresis and corneal resistance factor values were not statistically different among the groups; however, a trend for lower values was found for keratoconus and fellow eyes compared to controls. Data should be interpreted with caution because of the small sample.
authors.affiliation: Department of Ophthalmology, Federal University of São Paulo, Brazil. brunomfontes@terra.com.br
authors.forename: Bruno M
authors.initials: BM
authors.lastname: Fontes
authors.forename: Renato
authors.initials: R
authors.lastname: Ambrósio
authors.forename: Marcella
authors.initials: M
authors.lastname: Salomão
authors.forename: Guillermo C
authors.initials: GC
authors.lastname: Velarde
authors.forename: Walton
authors.initials: W
authors.lastname: Nosé
mesh_terms: D000293:Adolescent; D000328:Adult; D001696:Biomechanical Phenomena / Q000502:physiology*; D016022:Case-Control Studies; D003315:Cornea / Q000503:physiopathology*; D019781:Corneal Topography; D005260:Female; D007839:Functional Laterality; D006801:Humans; D007640:Keratoconus / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D010781:Photography; D014054:Tomography; D055815:Young Adult