Long-term Outcomes of Collagen Crosslinking for Early Keratoconus

Keratometry Changes Between Year Seven and Twelve After Corneal Crosslinking in Patients with Keratoconus

Background/Objectives: To evaluate the timing and extent to which late keratometric changes can occur between year 7 and 12 after corneal collagen crosslinking (CXL) in patients with keratoconus. Methods: A subgroup of a retrospective cohort study of all consecutive patients who underwent CXL at our cornea center between 2007 and 2011 was analyzed. The inclusion criteria consisted of CXL according to the Dresden protocol and a full set of keratometry parameters collected by Scheimpflug tomography preoperatively and at year 7, 9 and 12 after CXL. Results: A total of 46 eyes of 35 patients were included. The most relevant keratometric parameters (Kmax, TCT, K1, K2 and anterior astigmatism) decreased statistically significantly at year 7 after CXL, while there was no relevant difference for posterior astigmatism and the flat axes of anterior and posterior astigmatism. All keratometric parameters (except for K2) remained stable between year 7 and 12 without statistically significant change, according to mixed effect model regression analysis. BCVA improved statistically significant between the baseline and year 7 and remained stable until year 12. Suspected disease progression was noted in two patients (4.3%) between year 7, 9 and 12 post-CXL. Conclusions: Keratometric and functional results improve significantly 7 years after CXL in comparison to preoperative values and show very effective stabilization without clinically relevant changes up to year 12. However, while the risk of disease progression decreases remarkably after 7 years, in rare cases, suspected progression can occur even up to year 12. Therefore, regular control visits with keratometry measurements are advisable at least every 2 to 3 years in the late postoperative course.

Corneal cross-linking in patients with keratoconus: up to 13 years of follow-up

INTRODUCTION

To evaluate long-term safety and efficacy of corneal collagen cross-linking (CXL) in patients with keratoconus up to 13 years.

MATERIALS AND METHODS

In this mono-centre exploratory study, we included all consecutive patients who underwent CXL in our cornea centre from 01/01/2007 to 12/30/2011 and met the inclusion criteria. CXL was performed in all patients according to the Dresden protocol. Evaluation included best-corrected visual acuity (BCVA), topographic keratometry by Scheimpflug corneal tomography and endothelial cell count (ECC). Follow-up measurements were taken up to 13 years after treatment were compared with baseline values.

RESULTS

The study enrolled 168 eyes. The mean age of our patients was 26.3 years ± 7.8 years. A complete topographic dataset was available 1 year postoperatively for 142 eyes, 5 years postoperatively for 105 eyes, 10 years postoperatively for 61 eyes and 13 years postoperatively for 9 eyes. BCVA increased statistically significant after 1 year, 5 years and 10 years and non-significantly after 13 years. All keratometric parameters with exception of posterior astigmatism showed a statistically significant decrease after 1 year, 5 years and 10 years. After 13 years, the decrease was statistically significant only in Kmax, K2 and thinnest cornea. No significant changes in ECC were detected. Three eyes received Re-CXL, none of the eyes received penetrating keratoplasty and no infections occurred in this cohort.

CONCLUSIONS

CXL can slow down or even stop the progression of keratoconus in the majority of cases. The effect is long-lasting with excellent safety.