Corneal cross-linking (CXL) has been shown to be a safe and valid treatment option for progressive keratoconus and have shown an arrest of progression with a low failure rate of 0% to 2.8% in mild to moderate keratoconus. A Kmax value of more than 58 diopters (D) was suggested to be a relative contraindication for CXL as it has been reported that the post-CXL progression rate seems to be higher in advanced keratoconus. This was a retrospective analysis of outcomes of standard Dresden epi-off cross-linking in progressive keratoconus with preoperative Kmax >=58.0 D. Sixty-one eyes of 56 patients were included. Inclusion criteria were Kmax >=58.0 D and minimum follow-up of one year. Corneal topography and tomography were performed preoperatively and at one and two years. Mean Kmax was 63.9+/-6.1 D (mean+/-SD, range 58.2-87.0 D) preoperatively (n=61) and 62.9+/-5.9 D (range 54.6-82.5 D) after one year. This represented a significant decrease in steepness (p=0.0029). Mean pachymetry decreased significantly from 433.7+/-44.8 [mu]m preoperatively to 423.0+/-41.8 [mu]m (p=0.001) at one year. Progression occurred in 14 of the 61 eyes (23%) at one year, and five (8.2%) steepened more than 2.0 D. In the group with two year follow-up, mean Kmax was 63.0+/-5.0 D (range 58.2-87 D) before CXL and decreased to 61.5+/-4.8 D (range 53.6-78.3 D) at two years (p=0.001). Nine of the 50 eyes (18%) showed an increase of Kmax of >= 1 D SRI showed a significant decrease from 1.7+/-0.4 to 1.6+/-0.4 (p=0.01) after one year. There was no significant change in average keratometry or cylinder one year after CXL. The authors did not observe any severe or persisting complications. In summary, this study shows that in very steep keratoconus eyes and progressive disease, much higher tomographic progression than previously reported is seen after CXL.
Results of corneal cross-linking in very steep corneas
Reviewed by Bushra Thajudeen
Keratoconus progression after corneal cross-linking in eyes with preoperative maximum keratometry values of 58 Diopters and steeper.
