Long-term evaluation of eyes with central corneal thickness <400 µm following laser in situ keratomileusis.

PURPOSE: To study long-term refractive and visual outcomes of laser in situ keratomileusis (LASIK) in eyes with a postoperative thin central cornea. METHODS: In this retrospective observational case series, we studied 282 myopic eyes with a normal preoperative topographic pattern and postoperative thin corneas (<400 µm) that had at least 3 years of follow-up after LASIK in three private clinics. The main outcome measures were safety, efficacy, predictability, percent tissue altered, and complications. RESULTS: The mean postoperative central corneal thickness was 392.05 µm (range: 363.00-399.00 µm). After a mean follow-up of 6.89±2.35 years (standard deviation), the safety index was 1.17, the efficacy index was 0.94, and predictability (±1.00 diopter [D]) was 73.49. The mean residual stromal bed thickness was 317.34±13.75 µm (range: 275-356 µm), the mean flap thickness was 74.76±13.57 µm (range: 55-124 µm), and the mean percent tissue altered was 37.12%±3.62% (range: 27.25%-49.26%). No major complications were recorded. CONCLUSION: LASIK with a resultant central cornea thickness <400 µm seems to be effective, safe, and predictable provided that preoperative topography is normal and the residual stromal bed thickness is >275 µm.