Keratectasia in 2 cases with pellucid marginal corneal degeneration after laser in situ keratomileusis.

We report 2 patients who experienced progressive blurring of vision following myopic laser in situ keratomileusis (LASIK) in 1 eye (Case 1) and bilaterally (Case 2). High against-the-rule astigmatism, associated with perilimbal thinning inferiorly, was seen on refraction in all eyes. Regional corneal pachymetry confirmed the peripheral corneal thinning inferiorly. Corneal topography revealed the typical features of pellucid marginal corneal degeneration (PMCD) in the untreated eye of Case 1. Advanced changes were noted in the fellow eye. The corneal topography findings in Case 2 were similar to those seen in PMCD. Patients with early PMCD may present to the refractive surgeon with a stable refraction, normal corrected visual acuity, and adequate central corneal thickness. Corneal topography data along with regional corneal pachymetry must be interpreted carefully to detect these cases. Laser in situ keratomileusis can lead to a rapid progression of PMCD.