Posterior keratoconus. An expanded classification scheme based on corneal topography.

OBJECTIVE

The purpose of the study was to evaluate corneal changes in posterior keratoconus.

DESIGN

A retrospective review.

RESULTS

Distinct topographic patterns were identified. Generalized posterior keratoconus showed uniform corneal steepening. Localized central and paracentral posterior keratoconus showed corneal steepening, and localized peripheral posterior keratoconus showed corneal flattening overlying the area of corneal change. The changes in central and paracentral posterior keratoconus appear to progress with an increase in patient age. Unilateral disease may have more amblyogenic potential.

CONCLUSIONS

Posterior keratoconus manifests significant corneal surface alterations. The distinct topographic patterns seen probably warrant a further classification of localized posterior keratoconus into central-paracentral and peripheral varieties.