Tomographic parameters for the detection of keratoconus: suggestions for screening and treatment parameters.

Tomographic corneal evaluation has added significantly more information in the evaluation of the ectatic cornea. Additional information from the posterior cornea and a full corneal thickness map in addition to anterior corneal analysis has increased the ability to identify early and subtle corneal changes. Although these newer examination modalities have increased our sensitivity in refractive screening, problems still persist when attempting to assure treatment trials (such as collagen cross-linking) for early disease are performed to an appropriate patient population. This article will review past and present diagnostic capabilities with a particular emphasis on refractive screening and early treatment studies and stress the limitations of our current diagnostic ability when it comes to diagnosing early ectatic change.