The spectrum of topography found in keratoconus.

In order to more completely understand the topographic changes associated with keratoconus we performed computer-analyzed, digitized, videokeratoscopy (CADVK) on 23 patients with clinically documented keratoconus, using the EH-270 Corneal Topographer (Visioptic, Houston, TX). The majority of analyzed eyes demonstrated the classic picture of a well defined zone of inferior to inferotemporal steepening. However, several other topographic patterns were noted, including: nasal, superior, and central steepening, as well as extension of the inferior steepening superiorly. Additionally, significant flattening was found in some portions of the cornea away from the cone, particularly in the superonasal quadrant. In all cases, the precise location and degree of steepening could be easily defined. Interestingly, for both typical and atypical topographic patterns, marked symmetry between eyes in each patient was noted. The use of CADVK may allow for a more thorough appreciation of the diverse and complex topographic abnormalities associated with keratoconus, information which could aid in contact lens management and design.