Corneal Biomechanical Metrics and Anterior Segment Parameters in Mild Keratoconus

Corneal Biomechanical Metrics and Anterior Segment Parameters in Mild Keratoconus

Author Fontes, Bruno M. Autor UNIFESP Google Scholar
Ambrosio, Renato Google Scholar
Jardim, Daniela Google Scholar
Velarde, Guillermo C. Google Scholar
Nose, Walton Autor UNIFESP Google Scholar
Institution Universidade Federal de São Paulo (UNIFESP)
Ctr Microcirurgia & Diagnost
Renato Ambrosio Eye Inst
Universidade Federal Fluminense (UFF)
Abstract Purpose: To compare corneal hysteresis (CH), corneal resistance factor (CRF), spherical equivalent (SE), average central keratometry (K-Avg), corneal astigmatism (CA), corneal volume (CV), anterior chamber (AC) depth, and central corneal thickness (CCT) between patients with mild keratoconus and healthy controls and to estimate the sensitivity and specificity of CH and CRF in discriminating mild keratoconus from healthy corneas.Design: Comparative case series.Participants: Sixty-three eyes (40 patients) with mild keratoconus (group 1) and 80 eyes from 40 gender- and age-matched controls (group 2).Methods: Patients underwent a complete clinical eye examination, corneal topography (Humphrey ATLAS; Carl Zeiss Meditec, Dublin, CA), tomography (Pentacam; Oculus, Wetzlar, Germany), and biomechanical evaluations (ocular response analyzer; Reichert Ophthalmic Instruments, Depew, NY). the receiver operating characteristic (ROC) curve was used to identify cutoff points that maximized sensitivity and specificity in discriminating mild keratoconus from normal corneas.Main Outcome Measures: Corneal hysteresis, CRF, SE, K-Avg, CA, CV, AC depth, and CCT. the diagnostic performance of CH and CRF for detecting mild keratoconus was assessed using the ROC curve.Results: in group 1 versus group 2, the SE values (mean +/- standard deviation) were -3.55 +/- 2.87 diopters (D) versus -1.46 +/- 3.09 D (P = 0); K-Avg, 45.09 +/- 2.24 versus 43.24 +/- 1.54 D (P = 0); CA, 3.15 +/- 1.87 versus 1.07 +/- 0.83 D (P = 0); CV, 57.3 +/- 2.12 versus 60.86 +/- 3.39 mm(3) (P = 0); AC depth, 3.19 +/- 0.35 versus 3.05 +/- 0.43 mm (P = 0.0416); CCT, 503 +/- 34.15 versus 544.71 +/- 35.89 mu m (P = 0); CH, 8.50 +/- 1.36 versus 10.17 +/- 1.79 mmHg (P = 0); CRF, 7.85 +/- 1.49 versus 10.13 +/- 2.0 mmHg (P = 0). the ROC curve analyses showed a poor overall predictive accuracy of CH (cutoff, 9.64 mmHg; sensitivity, 87%; specificity, 65%; test accuracy, 74.83%) and CRF (cutoff, 9.60 mmHg; sensitivity, 90.5%; specificity, 66%; test accuracy, 76.97%) for detecting mild keratoconus.Conclusions: the values for CH, CRF, CV, and CCT were statistically lower and those for SE, K-Avg, CA, and AC depth were statistically higher in patients with mild keratoconus compared with controls. Corneal hysteresis and CRF were poor parameters for discriminating between mild keratoconus and normal corneas.Financial Disclosure(s): Proprietary or commercial disclosure may be found after the references. Ophthalmology 2010;117:673-679 (C) 2010 by the American Academy of Ophthalmology.
Language English
Date 2010-04-01
Published in Ophthalmology. New York: Elsevier B.V., v. 117, n. 4, p. 673-679, 2010.
ISSN 0161-6420 (Sherpa/Romeo, impact factor)
Publisher Elsevier B.V.
Extent 673-679
Access rights Closed access
Type Article
Web of Science ID WOS:000276638800005

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