Purpose:
To assess the long-term outcomes after cross-linking treatment of post-LASIK ectasia.
Methods:
Twenty-five eyes with topographically documented progressive post-LASIK ectasia were treated with cross-linking. The standard treatment procedure was used, applying riboflavin 0.1% following epithelial abrasion. The cornea was then irradiated with UVA light. The eyes were monitored for a minimum of 36 months. Best spectacle corrected visual acuity (BSCVA), refraction, topography, corneal thickness, as well as aberrations were dcumented at regular intervals.
Results:
At 36 months after cross-linking, mean BSCVA had significantly (p<0.05) improved from 0.46±0.25 to 0.69±0.22 (decimal scale). Sixty-three percent of the eyes had gained more than 2 lines of BSCVA at the three-year follow-up. Also at this point, 21% of the eyes had achieved a BSCVA of 1.0, while only 16% had attained 0.6 or worse. Mean spherical equivalent refraction had improved from -3.77D to -1.96D. Mean cylinder was lowered from -2.79D to -2.16D. Topography maps exhibited markedly reduced steepest points as early as 4 months following treatment, as well as stability of keratometry readings. Mean central corneal thickness decreased significantly (p<0.05) from 439±43 µm prior to cross-linking to 421±40 µm at 36 months. Similarly, mean thinnest point pachymetry showed a significant decrease from 431±45 µm to 411±45 µm during the follow-up period. While mean spherical aberration and mean corneal coma decreased during the 3 years, the differences were not statistically significant when compared with the preoperative data.
Conclusions:
This 3-year follow-up provides further evidence that corneal cross-linking is effective in arresting progressive post-LASIK ectasia. Cross-linking appears to stabilize iatrogenic ectasia even long-term. The parameters used to monitor the action of cross-linking on keractasia show results very similar to those obtained when treating progressive keratoconus.
Keywords: cornea: clinical science • refractive surgery: complications • refractive surgery: LASIK