Slitlamp, Specular, and Light Microscopic Findings of Human Donor Corneas after Laser-assisted in Situ Keratomileusis

Objective: To examine slitlamp, specular, and light microscopic features of human donor corneas known to have undergone laser-assisted in situ keratomileusis (LASIK). Methods: Twenty-six donor corneas known to have undergone LASIK prospectively underwent slitlamp examination with particular attention to the presence of a flap edge, as well as specular microscopy with particular attention to the presence of highly reflective particles in the stroma corresponding to the LASIK interface. Central endothelial cell density and pachymetery were obtained. They were compared with 26 control donor corneas without LASIK. Eleven LASIK donor corneas were processed for histology. Twenty-six donor corneas with no known prior keratorefractive surgery also underwent similar slitlamp examination and specular microscopy to serve as controls. Results: Twelve (46%) of 26 LASIK donor corneas had an obvious flap edge, and 10 (39%) had a subtle flap edge by slitlamp examination. Four (15%) had infiltrates by slitlamp examination, of which 3 were confirmed by histopathologic examination. Highly reflective particles were seen by specular microscopy in the stroma of 23 (88%) of 26 LASIK donor corneas, but only 1 (4%) of 26 control donor corneas had a single highly reflective particle in the stroma (P<001). The mean central endothelial cell counts were similar: 2138 cells/mm² in the LASIK group compared with 2250 cells/mm² in the controls (P=.39). Vacuolization and pyknosis of keratocytes was a consistent histopathologic finding after LASIK. Metallic particles at the interface were not detected by histology. Conclusions: Detection of a flap edge by slitlamp examination may detect at least half of the donor corneas that may have undergone LASIK. The detection of highly reflective stromal particles may form an effective basis for screening for LASIK donor corneas using specular microscopy and requires further study.