Impact of Donor Age and Cornisol Storage Duration on Endothelial Cell Count and Morphology in Donor Corneal Tissues: A Prospective Observational Study

Introduction: Corneal transplantation remains one of the most successful forms of solid tissue transplantation and a crucial treatment modality for visual rehabilitation in patients with corneal blindness. The success of keratoplasty is largely determined by the health of the corneal endothelium, a non regenerating monolayer crucial for maintaining corneal clarity. Factors such as donor age, cause of death and storage duration influence endothelial viability, especially in intermediate-term storage media such as Cornisol, widely used in Indian eye banks. Aim: To study and serially evaluate the donor corneal Endothelial Cell Count (ECC) and morphology during Cornisol storage, in association with donor age and cause of death. Materials and Methods: This prospective observational study was conducted at a tertiary care hospital and research centre, Pune, Maharashtra, India which included 75 donor corneoscleral rims stored in Cornisol between September 2023 and March 2025. Seventy-five donors were categorised into three age groups: Group I (0-30 years), Group II (31-60 years), and Group III (61-90 years). Specular microscopy was performed on days 0, 1, 3, 5, 7, 10 and 14, or until the end of storage. ECC, hexagonality (%HEX), and Coefficient of Variation (CV%) were analysed over time using repeated-measures Analysis of Variance (ANOVA) for intragroup comparisons, while one-way ANOVA followed by Tukey’s post hoc test was applied for intergroup comparisons. A p-value <0.05 was considered statistically significant. Results: Group I (0-30 years) had the highest baseline ECC and the lowest percentage ECC loss (7.8% by day 5). Group II (31- 60 years) showed the greatest ECC loss (36.5% by Day 14), followed by Group III (61-90 years) with 30.4% loss. Intragroup ECC decline was statistically significant in all groups (Group I: p-value=0.009; Groups II and III: p-value <0.001). Intergroup differences in ECC, hexagonality and CV were also significant across most time points (p-value <0.001, except day 14 for ECC where p-value=0.2206). Percentage ECC loss was highest in corneas from trauma-related deaths (45.3%), followed by cardiorespiratory failure (41.6%) and non traumatic intracranial haemorrhage (22.4%), with statistically significant differences across most time points (except day 5, p-value=0.071). Conclusion: Younger donor corneas demonstrated superior ECC and stability of morphometric parameters. Significant deterioration was noted in older donor tissues, especially beyond day 5 of storage. Donor age, storage duration and cause of death all influenced endothelial viability, supporting early use and careful donor selection.