Clinical Outcome of LASIK with Different Flap Thickness

ABSTRACT

PURPOSE: Since a few cases of keratectasia after LASIK were reported, the importance of residual corneal thickness has been emphasized. This study was to analyze adverse effects which may occur in reducing corneal flap thickness to increase residual corneal thickness. METHODS: A total of 237 eyes of 149 patients who had been followed up for 6 months or more after LASIK were evaluated retrospectively. Intended corneal flap thickness was 130 micrometer in 116 eyes(group A), and 160 micrometer in 121 eyes(group B) using an Automated Corneal Shaper(Chiron, USA). Clinical outcomes were compared between two groups. RESULTS: Except for some cases with retinal complication after surgery, 3 eyes lost best-corrected visual acuity by 2 lines or more in group A and 1 eye in group B, which was not statistically significant.(p>0.05) Fourteen eyes lost 1 line or more best-corrected visual acuity by postoperative irregular astigmatism in group A and 10 eyes in group B, which showed no significant difference, either. The incidence of flap-related complications such as wrinkling and free cap did not differ significantly between two groups(p>0.05). CONCLUSIONS: To leave residual cornea of greater thickness using a 130 micrometer thick flap rather than 160 micrometer may be a useful method to avoid postoperative keratectasia, one of the most severe complications.