Comparative evaluation of biomechanical changes and aberration profile following accelerated collagen cross-linking using hypo-osmolar and iso-osmolar riboflavin: A prospective study

Abstract

Purpose: To compare the changes encountered in corneal biomechanics and aberration profile following accelerated corneal collagen cross-linking (CXL) using hypo-osmolar and iso-osmolar riboflavin in corneal thicknesses of 400 microns, respectively. Methods: This is a prospective, interventional, comparative study involving 100 eyes of 75 patients with progressive keratoconus. Eyes were divided into two groups based on corneal thickness: group 1 included eyes with a corneal thickness of 400 microns who underwent iso-osmolar CXL. Corneal biomechanical and aberration profiles were evaluated and compared between groups. Results: In group 1, all higher-order aberrations (HOA) except secondary astigmatism significantly decreased from baseline; however, in group 2, only coma and trefoil decreased. The corneal resistance factor and corneal hysteresis significantly improved in both groups, which was significantly greater in group 2 than in group 1. The change in inverse radius, deformation amplitude, and tomographic biomechanical index was significantly improved in group 2 as compared to group 1. Conclusion: Improvement in corrected distance visual acuity and decrease in HOA were significantly better in the hypo-osmolar CXL group; however, the improvement in biomechanical strength of the cornea was significantly better in the iso-osmolar group.

Keywords

• accelerated collagen cross-linking
• corneal biomechanics
• higher-order aberration
• hypo-osmolar riboflavin
• iso-osmolar riboflavin
• keratoconus