Corneal Topography

PrefaceKiliç and Roberts have assembled a strong team of experts to create a treatise of extraordinary value to the eye care professionals. Modern corneal topography is presented from the fundamental concepts, to the descriptions of representative instruments available, to a selection of the many applications to which this technology has applied itself. The field began as a quest to show the pioneers of keratorefractive surgery how the corneal surface was surgically altered. This provided guidance for the remarkable achievements that followed. Corneal topography transitioned into the diagnostic arena to make the critically important diagnosis of keratoconus and other ectatic degenerative diseases to improve the safety of refractive surgery. Corneal topography data have become a precise guide for corneal laser ablation by coupling individual corneal elevation data to control laser sculpting of tissue. Accurate knowledge of corneal shape has altered the way we fit contact lenses in difficult cases.Corneal topography standards have been published or are in progress by the American National Standards Institute (ANSI), the International Organization for Standardization (ISO), and the Digital Imaging and Communications in Medicine (DICOM) workgroup. This underscores the fact that corneal topography is a mature science and a worldwide standard in anterior segment practice. However, we are not yet done. Improvements in the sensitivity and accuracy with the reflectiontype devices, slit-based devices, and interferometry-based instruments are nearly within our grasp. Adjunct technologies provide independent measurements that help to provide additional clues for early detection of corneal dystrophies. The availability of accurate global corneal pachymetry is an essential tool with which to detect abnormalities in corneal thickness that can be the only sign of impending disease. Biomechanical analysis is starting to yield clues about the efficacy of the stiffening effects of the corneal crosslinking procedures. Intelligent algorithms are incorporating combinations of available attributes for automatic diagnostics. Genetic analysis may eventually provide the clues necessary to forecast corneas prone to the development of an ectatic degenerative condition that weakens the stroma. In a field that began with the observation of distortions of window reflections from patients' corneas, we have come a long way. But with apologies to Robert Frost: we have "... miles to go before ..." we "... sleep."Stephen D. Klyce