Anatomic differences between a normal and two keratoconus corneas

ABSTRACT

Keratoconus is an anatomic deformity of the cornea characterized by progressive thinning and a cone-shaped protrusion of the central cornea. Thinning corneal disorders, such as keratoconus, should be identified before excimer laser refractive surgery.An Orbscan System (Orbscan Corneal Topography System II, Orbscan Inc., Salt Lake City, UT, USA) was used to analyse and compare corneal thickness values and the anterior and posterior corneal elevation maps of three subjects who wished to undergo excimer laser refractive surgery. The quantitative differences between the minimum thickness value of the entire cornea and the values obtained in the central and paracentral cornea of the subjects were also analysed.Analysis of corneal thicknessess revealed that normal corneas had higher central and paracentral values. Greater differences were found between the thinnest site of the entire cornea and the paracentral areas in the keratoconic corneas than in the normal cornea. Thecone-shaped protrusion was detected in the anterior and posterior corneal elevation maps of one subject but only in the posterior elevation map of the other keratoconus subject.The detection of corneal anatomic deformities,such as keratoconus, should include the analysisof corneal thickness values and the analysisof both anterior and posterior corneal elevationmaps (AU)

RESUMEN

No disponible