Evaluation of corneal graft quality in a human tissue bank: a 12-year retrospective study (2013–2025)

Abstract

Introduction The cornea is a transparent, avascular, and highly specialized structure located in the anterior segment of the eye, playing a critical role in focusing light onto the retina and ensuring clear visual perception. The quality of corneal grafts can be influenced by several factors related to the donor, the recipient, as well as the harvesting, preservation, and processing procedures performed within tissue banks. Corneal grafts are generally classified for optical use, aimed at restoring visual function, or tectonic use, intended to reestablish the structural integrity of the ocular globe. Materials and Methods A total of 537 corneas harvested from 290 donors were analyzed. Among the donors, 69.8% were male and 30.2% female, with a mean age of 59.4 ± 18.3 years, ranging from 18 to 91 years. Donor sources included forensic medicine departments (20.5%), public hospitals (70.6%), and multi-organ donors (7.1%). most common causes of death were cardiovascular diseases, traumatic injuries, and cerebrovascular disorders. Corneal harvesting was generally performed within 10 hours post-mortem, followed by macroscopic and microscopic evaluation, including assessment of endothelial cell density and morphological endothelial alterations such as polymegethism and pleomorphism. All tissues underwent serological screening for infectious diseases (HBsAg, HCV, HIV) and microbiological testing to detect bacterial or fungal contamination. Results The overall corneal graft invalidation rate was 25.4%. The main causes of exclusion included positive serological results (15%), biological contamination (6.8%), and hemolysis (1%). A total of 74.6% of corneas were used for transplantation, while 25.4% were discarded. Among the transplanted grafts, 44.8% were used for optical penetrating keratoplasty, 51.7% for tectonic keratoplasty, 2.1% for lamellar keratoplasty, and 1.3% for unspecified procedures. Microbiological analysis showed that bacterial contamination predominated (96.4%), mainly caused by Gram-positive bacteria (77%), particularly Staphylococcus aureus (78%) and Staphylococcus epidermidis (20%). Gram-negative bacteria (23%), especially Pseudomonas aeruginosa, were less frequent. Fungal contamination accounted for 3.6%, predominantly involving Candida albicans (91%). Conclusions. Early post-mortem harvesting, strict donor screening, and comprehensive microbiological control are essential for ensuring the quality and safety of corneal grafts used in transplantation. Corneas with high endothelial cell density are optimal for optical keratoplasty, while tissues with lower endothelial density remain valuable for tectonic reconstruction when preserved appropriately.