Excimer laser-assisted lamellar keratoplasty for the surgical treatment of keratoconus

PURPOSE: To evaluate the anatomical and functional results of excimer laser-assisted lamellar keratoplasty (ELLK) in keratoconus patients. SETTING: Eye Clinic, University of L'Aquila, L'Aquila, Italy. METHODS: This prospective case series comprised patients with keratoconus who had ELLK and were examined preoperatively and 3, 6, 12, and 24 months postoperatively. Outcome measures were uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), refraction, computerized videokeratography, pachymetry, and endothelial specular microscopy. RESULTS: Forty-one eyes (41 patients) were examined. The UCVA and BSCVA were significantly better at all follow-up examinations than preoperatively. After the 24-month follow-up (33 patients), the UCVA was better than 20/60 in 11 patients (33.3%) and the BSCVA was 20/40 or better in 29 patients (87.9%). The mean refractive astigmatism was 2.20 diopters (D) and the mean manifest retraction spherical equivalent refraction, -1.18 D. Corneal topographic patterns were regularly astigmatic in 28 (84.8%) of 33 eyes, and the mean corneal thickness (440.0 mu m) was significantly greater than preoperatively (553.0 mu m). No statistically significant changes in mean corneal endothelial cell density were observed postoperatively. Complications included corneal melting treated with penetrating keratoplasty (PKP) (1 case) and postoperative high refractive error requiring topographically guided excimer laser photoretractive keratectomy (7 cases). CONCLUSIONS: Two-year findings indicate that ELLK is as efficacious as PKP for the surgical treatment of moderate to advanced keratoconus. The procedure is relatively simple. Most steps can be standardized, and there are no time-consuming maneuvers