Biomechanical efficacy of corneal cross-linking using hypoosmolar riboflavin solution.

Abstract

PURPOSE:

The use of hypoosmolar riboflavin solution has been suggested for cross-linking thin corneas. The aim of this study was to compare the biomechanical efficacy of corneal cross-linking using hypoosmolar dextran-free riboflavin solution (HCXL) versus isoosmolar standard corneal cross-linking treatment (CXL).

METHODS:

A total of 24 postmortem porcine eyes with debrided corneas were subdivided into three treatment groups: Controls, the isoosmolar group with isoosmolar 0.1% riboflavin-20% dextran solution and the hypoosmolar group with dextran-free, 0.1% riboflavin solution. The samples were irradiated with UVA light of 365 nm wavelength and an irradiance of 3 mW/cm² for 30 min (dose 5.4 J/cm²). For the biomechanical measurements, 400-µm-deep anterior corneal flaps were created using a lamellar rotating microkeratome. Uniaxial stress-strain measurements were performed.

RESULTS:

In the isoosmolar treatment group, stress and Young's modulus at 8% strain were significantly increased by 67.97%, respectively, 62.62% versus the controls. In the hypoosmolar treatment group, stress and Young's modulus at 8% strain were significantly increased by 81.21%, respectively, 51.40% versus the controls. There was no significant difference between the iso- and hypoosmolar groups in biomechanical efficacy. On histology, there was no edema in the anterior 200 µm of the corneas after stromal swelling by the hypoosmolar riboflavin solution.

CONCLUSION:

Corneal cross-linking using isoosmolar or hypoosmolar riboflavin solution induces a comparable biomechanical effect. This is explained by the localization of the maximum cross-linking effect in the anterior 200 µm of the cornea which are not affected by the swelling effect of hypoosmolar riboflavin solution.

• Authors: Gregor Wollensak, Eberhard Spörl
• Journal: European journal of ophthalmology (Eur J Ophthalmol) Vol. 29 Issue 5 Pg. 474-481 (Sep 2019) ISSN: 1724-6016 [Electronic] United States
• PMID: 30255714 (Publication Type: Journal Article)

Chemical References

• Cross-Linking Reagents
• Photosensitizing Agents
• Collagen
• Riboflavin

Topics

• Animals
• Biomechanical Phenomena
• Collagen (metabolism)
• Cornea (drug effects, physiology)
• Corneal Stroma (metabolism)
• Cross-Linking Reagents
• Elastic Modulus (physiology)
• Osmolar Concentration
• Photochemotherapy (methods)
• Photosensitizing Agents (therapeutic use)
• Riboflavin (therapeutic use)
• Swine
• Ultraviolet Rays