Accelerated versus conventional corneal collagen cross-linking in the treatment of mild keratoconus: a comparative study

Abstract

Ahmed Mohamed SherifFaculty of Medicine, Cairo University, EgyptAim: To evaluate the use of accelerated corneal collagen cross-linking in the management of mild and moderate progressive keratoconus in comparison with conventional cross-linking.Patients and methods: Prospective randomized interventional case-control clinical trial. A total 25 eyes of 18 patients were randomly divided into two groups: group A included 14 eyes that received accelerated collagen cross-linking; and group B included eleven eyes that received conventional cross-linking (Dresden protocol). Cases with grade 1 and 2 keratoconus (Krumeich classification) with topographic evidence of progression were included. The uncorrected visual acuity and best spectacle-corrected visual acuity were recorded. Pentacam® corneal analysis imaging was used: The maximum and minimum keratometry and the central corneal thickness were recorded. Ocular Response Analyzer® (ORA) measurements were carried out to document the biomechanical parameters. Corneal hysteresis and corneal resistance factor were recorded. Postoperative evaluation included uncorrected visual acuity, best corrected visual acuity, and Pentacam and ORA measurements at 6 and 12 months. The follow-up period was 12 months.Results: A progressive decrease in the flat keratometry, steep keratometry, and mean keratometry was noted throughout the follow-up period in both the accelerated and conventional groups. The improvement in keratometry was not statistically significant. The best spectacle-corrected visual acuity showed a statistically significant improvement in both groups by 1 year. The corneal hysteresis and corneal resistance factor showed nonsignificant improvement in both groups. The central corneal thickness showed a significant thinning at 6 months in both groups but approached baseline values by 12 months.Conclusion: Accelerated corneal collagen cross-linking appears to show comparable results to conventional cross-linking in arresting the progression of mild keratoconus.Keywords: accelerated collagen cross-linking, corneal hysteresis, corneal resistance factor, central corneal thickness