Keratectasia after Laser in Situ Keratomileusis: Clinicopathologic Case Report

ABSTRACT

PURPOSE: To describe the morphological features of a prominent ectasia of the cornea after laser in situ keratomileusis (LASIK). METHODS: The morphology of the ectatic corneas were examined using corneal topography, optical microscopy and transmission electron microcopy in 2 cases who had undergone penetrating keratoplasty due to a poor visual acuity induced by progressive corneal ectasia after LASIK. RESULTS: On a topographic examination, the apex of the corneal surface was observed within the central 3 mm zone and the smallest thickness was 116 micrometer and 271 micrometer in each case. The histological examination showed that the epithelial layer had become thinner and detached easily. The Bowman's membrane was broken down and folded. An irregular arrangement of the stromal lamellae with the fibroblastic keratocytes was found. Scar tissue was observed between the epithelium and the Bowman's layer in the central region. In contrast, the corneal endothelium was intact and no abnormality was found in both cases. CONCLUSIONS: The morphologic examination of 2 cases with corneal ectasia revealed a forward protrusion of both the anterior and posterior corneal surface. In addition epithelial detachment, breakage and folding of the Bowman's membrane and irregular lamellae were found. The 2 cases had greatly thinned and protruding corneas, yet there was no abnormality in the corneal endothelium.