The Efficacy and Safety of Oxygen-Enriched Rose Bengal and Green Light Corneal Crosslinking.

PURPOSE: To evaluate the efficacy and safety of Rose Bengal (RB) and green light crosslinking (RGX) with supplemental oxygen.

METHODS

Rabbits were divided into three groups. Rabbits in the control group were de-epithelialized and served as controls. Rabbits in the RGX-nO2 group were de-epithelialized, stained with 0.1% RB for 20 minutes, and then exposed to green light at 0.25 W/cm2 for 10 minutes in an ambient atmospheric oxygen environment. Rabbits in the RGX-hO2 group received the same treatment as group 2, but supplemental oxygen was given to the ocular surface during irradiation. Central corneal thickness was measured at various points during RGX. After RGX, corneal microstructure, corneal biomechanics, and resistance to enzyme lysis were evaluated.

RESULTS

RGX-hO2 and RGX-nO2 significantly increased the corneal tensile strength by factors of 1.76 and 1.46, respectively. The times for complete corneal digestion within the RGX-hO2, RGX-nO2, and control groups were 23.2 ± 1.1 hours, 18.0 ± 2.0 hours, and 8.4± 0.9 hours. The average collagen fibril diameters (43.58 ± 0.93 nm, 40.46 ± 1.11 nm, and 35.25 ± 0.75 nm, respectively) and surface-to-surface spacing (11.67 ± 1.91 nm, 15.51 ± 1.66 nm, and 24.93 ± 1.95 nm, respectively) also differed statistically among the three groups. No evidence of endothelial or stromal cell damage was detected by endothelial staining or TUNEL assay.

CONCLUSIONS

Increasing the concentration of oxygen during the irradiation process enhances RGX efficacy without causing obvious damage to a rabbit's endothelium or stromal cells.

TRANSLATIONAL RELEVANCE: The study can potentially help with improvement of the existing clinical crosslinking protocol.