Corneal assessment technologies: current status

Abstract

There are now many devices that acquire data about the cornea: shape, power, pachymetry at any desired point of the cornea, corneal hysteresis, flap thickness (in LASIK procedures), endothelial cell count and morphology, and so forth. We review the literature on corneal assessment techniques and devices available in clinical practice. Specifically, we discuss slit lamp biomicroscopy, specular microscopy, ultrasound pachymetry, confocal microscopy, very-high-frequency digital ultrasound biomicroscopy, optical coherence tomography, Placido disk-based keratoscopy, slit-scanning elevation topography, Scheimpflug imaging, and dynamic applanation procedures-all of which can be used to assess the morphology of the cornea. In addition, we present a critical analysis of the instrumentation described and discuss the necessity of developing new technology for assessing both the morphology and the physiology of the cornea.

Keywords: Orbscan topography; confocal microscopy; corneal morphology assessment; dynamic applanation procedures; optical coherence tomography (OCT); placido disk; scheimpflug imaging; specular microscopy; ultrasound pachymetry; very high-frequency (VHF) digital ultrasound biomicroscopy.