High myopia as a risk factor for post-LASIK ectasia: a case report.

Purpose To describe the case of a patient developing corneal ectasia following LASIK for the correction of myopic astigmatism. Materials and Methods A 39-year-old man underwent bilateral uneventful LASIK for myopic astigmatism of -10.25 -1.75 ×040 OD and -8.00 -2.50 ×005 OS. Preoperative corneal pachymetry was 542 micrometers OD and 543 micrometers OS. Preoperative corneal topography showed bilateral oblique bow-tie patterns. Central keratometry measurements were 45.12 D @ 124 / 43.87 D @ 34 OD and 44.87 D @ 78 / 43.12 D @ 168 OS. Keratoconus or forme fruste keratoconus were not present preoperatively. Results The residual stromal bed was 314 micrometers OD and 295 micrometers OS. Increasing astigmatism was documented progressively after LASIK. Central keratometry and topography were performed with evidence of ectasia OD at 17 months post-operatively and early evidence of ectasia OS at last follow-up of 58 months. Conclusion High myopia appears to be a predisposing factor in this patient. High myopia may need to be considered as an ectasia risk factor independent of amount of ablation or residual stromal bed thickness and in the absence of forme fruste keratoconus. The possibility remains that ectasia was due to an unidentified risk factor or an intrinsic corneal problem with this patient's right eye.