Changes in corneal topography after laser in situ keratomileusis for myopia

OBJECTIVE: To define qualitative patterns of corneal topography after excimer laser in situ keratomileusis (LASIK) and to assess whether epithelial hyperplasia occurred after LASIK. METHODS: A consecutive series of 18 myopic eyes of 10 patients having refractive surgery in an academic practice at the Royal Victorian Eye and Ear Hospital, Melbourne, Australia was followed prospectively after LASIK. Four eyes were treated with the VISX 20/20 excimer laser and 14 eyes were treated with the Nidek EC5000 excimer laser. Videokeratography was performed on each eye at 1, 3, and 6 months after surgery. The common digital subtraction topographic patterns were classified and used to speculate whether epithelial hyperplasia occurred. RESULTS: After LASIK, 83% of subtraction maps at 1 month and 81% at both 3 and 6 months showed steepening in the ablation zone. There was no clear correlation between the topographic maps and spectacle-corrected visual acuity or regression of the initial effect after surgery. CONCLUSION: Corneal topographic changes similar to those seen after photorefractive keratectomy (PRK) occur after LASIK for myopia.