Predicting corneal cross-linking treatment efficacy with real-time assessment of corneal riboflavin concentration.

PURPOSE

To assess predictability of tissue biomechanical stiffening induced by UV-A light-mediated real-time assessment of riboflavin concentration during corneal crosslinking (CXL) of human donor tissues.

SETTING

Studio Italiano di Oftalmologia, Rome, Italy.

DESIGN

Laboratory study.

METHODS

20 sclerocorneal tissues were randomly stratified to undergo CXL with either the epithelium intact (n = 12) or removed (n = 8). Samples underwent corneal soaking with 0.22% riboflavin formulation (RitSight) with dosing time of t = 10 minutes and t = 20 minutes in epithelium-off and epithelium-on protocols, respectively. All tissues underwent 9-minute UV-A irradiance at 10 mW/cm 2 using theranostic device (C4V CHROMO4VIS). The device used controlled UV-A light irradiation to induce both imaging and treatment of the cornea, providing a real-time measure of corneal riboflavin concentration and treatment efficacy (ie, theranostic score) during surgery. Tissue biomechanics were assessed with an air-puff device (Corvis), which was performed before and after treatment. A 3-element viscoelastic model was developed to fit the corneal deformation response to air-puff excitation and to calculate the mean corneal stiffness parameter (k c ).

RESULTS

Significant corneal tissue stiffening ( P < .05) was induced by the theranostic UV-A device in either CXL treatment protocol. Significant correlation was found between the theranostic score and the increase in k c ( R = 0.75; P = .003). The score showed high accuracy (94%) and precision (94%) to predict correctly samples that had improved tissue biomechanical strengthening.

CONCLUSIONS

Real-time assessment of corneal riboflavin concentration provided a predictive and precise approach for significant improvement of tissue strength on individual corneas, regardless of CXL treatment protocol.