Analysis of 2-year corneal cross-linking results in keratoconus patients

Purpose

To analyze the results of 2 years of corneal collagen cross-linking (CXL) for the treatment of keratoconus and to detect the efficiency of this procedure.

Design

This was a retrospective noncomparative study.

Patients and methods

A total of 58 eyes of 40 keratoconus patients were subjected to CXL. Epithelium-off CXL was the only procedure performed for all cases. The preoperative and postoperative measures included uncorrected visual acuity, best-corrected visual acuity (BCVA), fundus examination, slit-lamp examination, pachymetry, keratometry, refractometry, and corneal topography. All eyes included in this study were followed up at 1, 3, 6, 12, and 24 postoperative months. All preoperative and postoperative data of all eyes were collected, revised, and analyzed.

Results

This study showed that uncorrected visual acuity improved by at least one line in 70.7% of the eyes in the study, but remained stable in 22.4% of the eyes in the study. BCVA improved by at least one line in 53.4% of the eyes in the study, but remained stable in 36.2% of the eyes in the study. Astigmatism remained stable in 86.2% of the eyes in the study and decreased by a mean of 1.20 D in 13.8% of the eyes in the study. The average keratometry (K) decreased by more than 1 D in 74.1% of the eyes in the study, but remained stable in 13.7% of the eyes in the study. The maximum K value decreased by a mean of 2.47 D in 55.1% of the eyes in the study, but remained stable in 38% of the eyes in the study. The K value of the apex decreased by a mean of 2.73 D in 65.5% of the eyes in the study, but remained stable in 25.9% of the eyes in the study.

Conclusion

This study proved that corneal cross-linking is beneficial both as a visual-preserving and as a visual-improving procedure. K readings are the main indicator of the success or the failure of the procedure. Central corneal thickness can be an indicator of improvement; there is a reciprocal relationship between the central corneal thickness and the BCVA. The best chance is for patients with corneal thickness more than 400 μm. It is advised that the refractive surgeon should store the riboflavin in the refrigerator from +4°C to +8°C and discard it immediately after surgery. The use of steroid from the first postoperative day was helpful. Most postoperative visual improvements resulted from a decrease in myopia, whereas there was no remarkable improvement in astigmatism.