Disinfection of Human and Porcine Corneal Endothelial Cells by Far-UVC Irradiation

Background and Objectives: The cornea protects the eye from external influences and contributes to its refractive power. Corneas belong to the most frequently transplanted tissues, providing a last resort for preserving the patient's vision. There is a high demand for donor corneas worldwide, but almost 4% of these transplants are not eligible due to microbial contamination. The objective of this study is to ascertain the suitability of 222 nm Far-UVC irradiation for the decontamination of corneas without damaging corneal endothelial cells. Materials and Methods: To assess the destructive effect of irradiation and, thus, identify the applicable dose needed to decontaminate the cornea without interfering with its integrity, 141 porcine corneas were irradiated with 0, 60 or 150 mJ/cm² at 222 nm. In the second step, a series of 13 human corneas were subjected to half-sided irradiation using 15 or 60 mJ/cm² at 222 nm. After five days of in vitro culturing, the endothelial cell density of the non-irradiated area of each human cornea was compared to the irradiated area. Results: Irradiation with up to 60 mJ/cm² had no detectably significant effect on the cell integrity of human corneas (p = 0.764), with only a minimal reduction in cell density of 3.7% observed. These findings were partially corroborated by tests on porcine corneas, wherein the variability between test groups was consistent, even at increased irradiation doses of up to 150 mJ/cm², and no notable effects on the irradiated porcine endothelium were monitored. The efficacy of the antimicrobial treatment was evident in the disinfection tests conducted on corneas. Conclusions: These initial irradiation experiments demonstrated that 222 nm Far-UVC radiation has the potential to decontaminate the cornea without compromising sensitive endothelial cell viability.