The Impact of Corneal Oedema on UV Light Transmission: An Experimental Study in Porcine Eyes

Background/Objectives: Corneal oedema is known for changing the cornea's optical properties, particularly its ability to transmit ultraviolet (UV) light, which is crucial for visual clarity and eye health. This study explores how changes in corneal thickness in oedematous states affect UV light transmission. Methods: This study included 107 porcine eyes with artificially induced corneal oedema. Corneal thickness (CCT) was measured histologically, UV transmittance was assessed using a UV/VIS spectrometer, and endothelial cell parameters were evaluated with specular microscopy. Statistical analyses included the Kruskal-Wallis test, Mann-Whitney U test, and Spearman's correlation. Results: The findings indicated a significant increase in CCT in oedematous corneas at 24 and 48 h post extraction compared to controls, with median CCT values of 816.59 ± 139.71 μm for controls, 1022.40 ± 234.48 μm at 24 h, and 1074.21 ± 220.83 μm at 48 h (p < 0.001). UV transmittance (395-280 nm) decreased substantially, dropping from 50.79 ± 7.65% in controls to 43.24 ± 5.35% at 24 h and 39.66 ± 6.51% at 48 h (p < 0.001). There was a significant negative correlation between CCT and UV transmittance (ρ = -0.346, p < 0.001). Endothelial parameters showed notable changes: maximum cell area (Area_MAX) decreased at 24 and 48 h, while endothelial cell density (ECD) increased at 24 h. Conclusions: Our study found a substantial inverse link between CCT and UV light transmission in oedematous corneas, highlighting the importance of UV protection, especially in individuals who are prone to recurrent oedema. Changes in CCT and endothelial measures, such as Area_MAX and ECD, are useful signs of corneal integrity. However, the study's small sample size and potential tissue modifications during processing need more research with bigger, in vivo samples to corroborate these findings and improve therapeutic use.