Major ReviewCorneal assessment technologies: Current status
Section snippets
Corneal morphology
The cornea is the major refractive element of the eye, contributing approximately 43 of the 60 diopters (D) of the eye optical system and accounting for approximately 70% of the total refraction.20 The cornea measures approximately 11 mm vertically and 12 mm horizontally in adults58 (with differences in moderate and high degrees of myopia, which results in lower white-to-white diameters68), and its anterior radius of curvature averages 7.8 mm.20 The cornea is approximately 535 μm thick,25 and
Corneal assessment technologies: Current status
In 1619, Father Christopher Scheiner observed that glass spheres of different radii reflected images of different sizes onto the cornea, and he determined the corneal curvature by matching the size of the images with that produced by the spheres.79 Since then, the biggest advances were made during the 20th century, with the rapid development of new technologies. We review the most important features of the different technologies—from slit-lamp biomicroscopy, first introduced in 1911, to
Discussion
The corneal assessment devices described in this review are among the most common options to clinically assess and evaluate the cornea and the anterior segment of the eye. They are capable of providing a wide range of data: corneal shape, power, pachymetry and hysteresis, flap thickness (after LASIK procedures), epithelial and endothelial cell morphology, and so forth. Moreover, these devices have multiple applications in eye examination and eye disease diagnosis.
It seems that there already
Conclusion
Current corneal assessment technologies make the process of corneal evaluation extremely fast and simple. Despite the significant progress that has been made, the necessity of developing new devices to gain a full understanding of corneal physiology is evident. The SLB is a traditional technique required when performing a correct and complete assessment of the anterior eye anatomy and identifying clinical signs, pathologies or alterations of the cornea. In many cases, however, the different
Method of literature search
We performed an extensive electronic search of the Medline and PubMed databases using individual and combinations of key words (cornea, pachymetry, thickness, epithelium, stroma, endothelium, flap, slit-lamp, biomicroscopy, ultrasound, high-frequency, tomography, specular, confocal, placido, topography, scheimpflug, and microscopy) in December 2013 to identify the relevant publications in this field. We also included additional references (from different sources) that were cited in these
Disclosure
The authors report no proprietary or commercial interest in any product mentioned or concept discussed in this article.
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