Two-year changes in corneal stiffness parameters after accelerated corneal cross-linking.

Area of Science:

• Ophthalmology
• Biomechanical Engineering
• Corneal Science

Background:

• Corneal cross-linking (CXL) is a treatment to strengthen the cornea.
• Assessing the biomechanical changes after CXL is crucial for understanding treatment efficacy.
• Dynamic corneal response (DCR) parameters offer insights into corneal biomechanics.

Purpose of the Study:

• To compare two-year changes in dynamic corneal response (DCR) between 18 mW/cm² (5-min) and 9 mW/cm² (10-min) CXL protocols.
• To utilize novel stiffness parameters and correlate them with clinical indices.
• To evaluate the efficacy of different CXL protocols using Corvis ST.

Main Methods:

• A non-randomized trial involving two groups: 5-min (18 mW/cm²) and 10-min (9 mW/cm²) CXL.
• Corvis ST measurements of DCR parameters (DA ratio, integrated radius, SP-A1) were taken before and two years after CXL.
• Statistical analysis was performed on follow-up data from 16 eyes (5-min group) and 21 eyes (10-min group).

Main Results:

• Both CXL protocols led to corneal strengthening over two years.
• The 10-min (9 mW/cm²) group showed significant decreases in DA ratio-2mm and integrated radius, and a significant increase in SP-A1.
• The 5-min (18 mW/cm²) group showed a significant reduction in integrated radius.
• Strong correlations were observed between DCR parameters and changes in the radius of curvature in both groups.

Conclusions:

• Both 5-min and 10-min CXL protocols effectively strengthen the cornea.
• The 9 mW/cm² (10-min) protocol demonstrated more significant biomechanical improvements.
• Corvis ST indices provide in vivo biomechanical evidence of CXL efficacy, potentially preceding clinical changes.