To provide an overview of the topographic and tomographic indices developed for detecting keratoconus (KC) and subclinical keratoconus.
Literature review of studies describing and testing KC indices as well as indices developed for improving the sensitivity of subclinical KC detection.
Several indices, based on anterior and posterior curvature measurements, corneal spatial distribution or posterior corneal elevation have been developed for improving the detection of KC and subclinical KC. However, to date, none of them could reach, alone, sufficient discriminating power for differentiating the mildest forms of the disease from normal corneas. New detection programs, based on a combination of corneal indices, and generated using artificial intelligence emerged recently and helped to significantly improve the subclinical KC detection.
The combination of topographic and tomographic corneal indices has helped to significantly improve the sensitivity of subclinical KC detection. However, combining these morphological indices to wavefront and biomechanical analyses of the cornea will certainly further improve the sensitivity of the future screening tests.
How to cite this article
Smadja D. Topographic and Tomographic Indices for Detecting Keratoconus and Subclinical Keratoconus: A Systematic Review. Int J Kerat Ect Cor Dis 2013;2(2):60-64.
Topographic and tomographic properties of forme fruste keratoconus corneas. Invest Ophthalmol Vis Sci 2010;51(11):5546-5555.
Contribution of the corneal epithelium to anterior corneal topography in patients having myopic photorefractive keratectomy. J Cataract Refract Surg 2007;33(11):1860-1865.
Epithelial, stromal, and total corneal thickness in keratoconus: three-dimensional display with artemis very-high frequency digital ultrasound. J Refract Surg 2010;26(4):259-272.
Comparison of front-surface corneal topography and Bowman membrane specular topography in keratoconus. J Cataract Refract Surg 2012;38(6):1043-1049.
Comparison of and correlation between anterior and posterior corneal elevation maps in normal eyes and keratoconus-suspect eyes. J Refract Surg 2007:789-795.
Corneal ectasia after LASIK despite low preoperative risk: tomographic and biomechanical findings in the unoperated, stable, fellow eye. J Refract Surg 2010;26(11):906-911.
Changes in anterior and posterior corneal curvatures in keratoconus. Ophthalmology. 2000;107(7):1328-1332.
Corneal volume, pachymetry, and correlation of anterior and posterior corneal shape in subclinical and different stages of clinical keratoconus. J Cataract Refract Surg 2010;36(5):814-825.
Comparative evaluation of elevation, keratometric, pachymetric and wavefront parameters in normal eyes, subclinical keratoconus and keratoconus with a dual scheimpflug Analyzer. Int J Kerat Ect Cor Dis 2012;1(10): 1-9.
Role of Orbscan II in screening keratoconus suspects before refractive corneal surgery. Ophthalmology 2002;6420(02):1642-1646.
Evaluation of keratometric, pachymetric, and elevation parameters of keratoconic corneas with pentacam. Cornea 2009;28(9):976-980.
Sensitivity and specificity of posterior corneal elevation measured by Pentacam in discriminating keratoconus/subclinical keratoconus. Ophthalmology 2008;115(9):1534-1539.
Evaluation of Scheimpflug imaging parameters in subclinical keratoconus, keratoconus, and normal eyes. J Cataract Refract Surg 2011;37(6):1116-1124.
Comparative evaluation of refractive surgery candidates with Placido topography, Orbscan II, Pentacam and wavefront analysis. J Cataract Refract Surg 2008;34:623-631.
Detection of subclinical keratoconus using an automated decision tree classification. Am J Ophthalmol 2013;156(2):237-246.
Use of a support vector machine for keratoconus and subclinical keratoconus detection by topographic and tomographic data. Ophthalmology. 2012;119:2231-2238.
Corneal epithelial thickness profile in the diagnosis of keratoconus. J Refract Surg 2009;25:604-610.
An introduction to understanding elevation-based topography : how elevation data are displayed – a review. Clin Experiment Ophthalmol 2008;(1):1101-1106.
The role of reference body selection in calculating posterior corneal elevation and prediction of keratoconus using rotating Scheimpflug camera. Acta Ophthalmologica 2011;89(3):251-256.
Influence of the reference surface shape for discriminating between normal corneas, Subclinical Keratoconus and Keratoconus. J Refract Surg 2013;29(4):274-281.
Corneal elevation topography: best fit sphere, elevation distance, asphericity, toricity and clinical implications. Cornea 2011;30(5):508-515.
Evaluation of keratoconus in Asians: role of Orbscan II and Tomey TMS-2 corneal topography. Am J Ophthalmol 2007;143(3):390-400.
Accuracy of ultrasonic pachymetry and videokeratography in detecting keratoconus. J Cataract Refract Surg 1998;24(2):196-201.
Keratoconus: spatial variation of corneal thickness as a diagnostic test. Arch Ophthalmol 1969;82:182-188.
Corneal-thickness spatial profile and corneal-volume distribution: tomographic indices to detect keratoconus. J Cataract Refract Surg 2006;32(11):1851-1859.
Novel pachymetric parameters based on corneal Tomography for diagnosing Keratoconus. J Refract Surg 2011;27(10):753-758.
Percentage thickness increase and absolute difference from thinnest to describe thickness profile. J Refract Surg 2010;26(2):84-86.
A new pachymetrybased approach for diagnostic cutoffs for normal, suspect and keratoconic cornea Eye 2012;26(5):650-657.