[Corneal topography of keratoconus]

The present study was designed to evaluate the topography of a series of keratoconus patients.

Using a computer-assisted videokeratography (Eye Sys) we determined the topographic findings of 85 eyes of 46 consecutive patients with keratoconus. We analysed some quantitative topographic parameters like: power at the apex, central corneal power, the amount of irregular astigmatism, distance between the apex and the visual axis, difference in central corneal power between the two eyes of the same individual and steepening of the inferior cornea compared with the superior cornea.

Keratoconic topographic alterations were classified into two groups. Fifty seven of the cones (71%) could be described as peripheral with steepening of the cornea extending to the limbus. The remaining twenty three eyes (29%) had steepening confined to the central cornea. In many instances corneal topography was characterized by a high degree of nonsuperimposable mirror image symmetry (enantiomorphism) in the location of the topographic alterations between the two eyes of an individual patient. In all patients, irrespective of the topographic pattern, the inferior midperipheral cornea was steeper than superior cornea as quantified by an l-S value.

Study of the topography in keratoconus using this technique may prove useful for documenting the pattern of involvement of the anterior corneal surface and providing insight into the pathogenesis of this condition.