Comparison between standard and transepithelial corneal crosslinking using a theranostic UV-A device

Area of Science:

• Ophthalmology
• Biomedical Engineering
• Corneal Science

Background:

• Corneal crosslinking (CXL) is a treatment to strengthen the cornea.
• Effective riboflavin concentration in the corneal stroma is crucial for CXL efficacy.
• Novel devices are needed to monitor riboflavin levels during CXL procedures.

Purpose of the Study:

• To compare corneal riboflavin concentration between conventional and iontophoresis-assisted transepithelial CXL protocols.
• To evaluate the utility of a novel image-guided theranostic UV-A device for real-time riboflavin assessment.

Main Methods:

• Ten human donor corneas were divided into two groups (n=5 each).
• Group 1: Conventional CXL (30 min stromal soaking, 30 min UV-A irradiance at 3 mW/cm²).
• Group 2: Iontophoresis-assisted CXL (5 min soaking, 9 min UV-A irradiance at 10 mW/cm²).
• A theranostic UV-A device with hyperspectral imaging was used for real-time riboflavin concentration monitoring.

Main Results:

• Manual stromal application resulted in significantly higher riboflavin concentration (425 ± 77 μg/cm³) compared to iontophoresis (195 ± 35 μg/cm³).
• Corneal riboflavin concentration decreased exponentially with UV-A irradiation in both protocols.
• Post-treatment riboflavin levels decreased by ≥85% in both groups.

Conclusions:

• Manual stromal riboflavin delivery achieved nearly 50% greater corneal concentration than transepithelial iontophoresis.
• The theranostic UV-A device offers a non-invasive method for monitoring riboflavin concentration during CXL.
• Further research may optimize iontophoresis protocols for improved riboflavin uptake.