Five-Year Long-Term Results of Standard Collagen Cross-Linking Therapy in Patients with Keratoconus

Objectives: We aimed to demonstrate the 5-year visual, topographic, and aberrometry long-term results of standard collagen cross-linking (CCL) treatment in keratoconus patients. Materials and Methods: The files and topographic measurements of patients who underwent standard CCL treatment for progressive keratoconus were retrospectively reviewed. Uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), refraction values, and topographic values were evaluated. Results: Thirty-seven eyes of 27 patients were included in the study. The female to male ratio was 15 (56%)/12 (44%) and the mean age was 22.16±6.4 (12-39) years. The increase in UCVA and BCVA was statistically significant at postoperative 1-5 years (all p values <0.05). The changes in the spherical equivalent after CCL were not statistically significant (p>0.05), but the decrease in the manifest astigmatism values were significant after CCL at 3-5 years (p<0.05). Decrease in K2 (steep keratometry) and K apex values were statistically significant at 1-5 years (p<0.05). There was a significant decrease in the thinnest corneal thickness compared to the preoperative values up to 6 months and 1-4 years (p<0.05), but the change at 5 years was not significant (p=0.08). Post-CCL reductions in high-order aberrations and spherical aberrations were significant at postoperative 5 years and 3-5 years (p<0.05). Conclusion: In long-term follow-up, CCL treatment is seen to arrest keratoconus progression, increase vision, and improve visual quality by reducing higher-order aberrations and spherical aberrations. For these reasons, CCL treatment continues to be the first treatment modality in patients with progressive keratoconus.