Rapid Warming of Donor Corneas Is Safe and Improves Specular Image Quality

To determine whether warming donor corneas to near-physiological temperatures can safely shorten warming times while providing high-quality specular images during tissue evaluation.

Mated corneas were warmed at room temperature (RT) or at 35°C for 4 hours upon removal from cold storage. Specular images and endothelial cell densities were acquired and rated every hour. Additional mated corneas were subjected to 2 rounds of 4-hour incubation at either RT or 35°C. Endothelial cell loss (ECL) was quantified 14 days after the initial incubation using Calcein-acetoxymethyl (Calcein-AM) and FIJI trainable segmentation. Cultures inoculated with common ocular pathogens were subjected to 2 warming cycles at RT for 4 hours or 35°C for 2 hours. Colony counts were taken over the course of 2 weeks after inoculation.

Specular image quality ratings were consistently higher for corneas warmed at 35°C compared with those at RT. Image quality ratings for corneas warmed at 35°C for 1.5 hours were higher than corneas warmed at RT for 4 hours (P = 0.04). No differences in ECL were observed between the 2 warming conditions (RT = 13.1% ± 7.6% ECL, 35°C = 13.9% ± 6% ECL, P = 0.75). There was no difference in colony counts for pathogens tested between the 2 warming conditions.

Warming donor corneas to near-physiological temperatures for a short time can increase specular image quality while reducing the time tissues are unrefrigerated at eye banks. This method allows for more efficient specular imaging without inducing additional ECL or increasing pathogen growth.