Technology for obtaining an ultrathin posterior lamellar corneal graft at the Eye Tissue Bank

Abstract

Objective: to develop technologies for preoperative preparation of the posterior lamellar corneal graft based on our own formulation of the preservation medium for optimal dehydration of the donor cornea and a technique for cutting out an ultrathin flap using an optimized method at the Eye Tissue Bank. Materials methods. In a series of experimental studies, we obtained data on the hydration level of cadaveric donor corneas that were preserved in various solutions at different observation periods. Using 16 corneas, analytical weighing and pachymetry were performed via optical coherence tomography in the experimental (n = 8) and control (n = 8) groups. Morphological and functional characteristics of the corneal endothelium were then assessed. At the next stage of work, ultrathin grafts were formed from 16 corneas after hypothermic preservation in the experimental (n = 8) and control (n = 8) solutions by single-pass microkeratome, followed by microscopy of the samples using a scanning electron microscope. Results. After the first days of preservation in the proposed solution, there was dehydration of 9% cornea in the experimental group in comparison with the samples of the control group. After 4 days of preservation, there was no reliable difference found between the groups (p > 0.05) in the study of the endothelial cell viability of ultra-thin corneal grafts by immunofluorescent microscopy using the «Live and dead» marker. Scanning electron microscopy revealed that corneal stromal collagen fibers, preserved in the proposed medium, retained their integrity. Conclusion. The proposed technology can be recommended for use at eye banks for formation of an ultra-thin corneal graft at the preoperative stage.