Changes of donor corneal endothelial cell morphology and density from eye bank before and after keratolasty and analysis of influencing factors

MethodsAn observational case series study was performed.A total of 118 donor corneas, retrieved by the Shandong Province Eye Bank between July 2020 and June 2021 for penetrating keratoplasty (PKP) and endothelial keratoplasty (EK) were included.Among them, 99 corneas (83.90%) were used for PKP, and 19(16.10%) for EK.The basic information of donors and the results of corneal quality tests were analyzed and compared with ECD measured by endothelial microscopy one month after keratolasty.Morphological changes in endothelial cells before and after surgery were observed, and factors influencing corneal ECD and morphology were analyzed.This study adhered to the Declaration of Helsinki.The study protocol was approved by the Ethics Committee of Shandong Eye Hospital (No.SDSYKYY20170319).Written informed consent was obtained from each subject.

Results  Among the 99 donor corneas for PKP, there were statistically significant differences in preoperative donor corneal ECD and 1-month postoperative ECD of implant among different age groups ( F=18.136, 5.936; both P<0.01), which were lower in the 31-60-year-old group and the >60-year-old group than in the 0-30-year-old group and higher in the 31-60-year-old group than in the >60-year-old group, with statistically significant differences (all P<0.01).There were statistically significant differences in the preoperative donor corneal ECD among different donor cause of death groups ( F=4.524, P<0.01), which was higher in the traumatic accident group compared to the cardiovascular and cerebrovascular disease group, chronic organ failure group and malignant tumor group (all P<0.01).The preoperative donor ECD in the death-tissue retrieval time ≤6 hours group was (2 577.66±284.63)cells/mm ², which was higher than (2 372.46±399.75)cells/mm ² in the death-tissue retrieval time >6 hours group, with a statistically significant difference ( t=2.289, P<0.05).There were statistically significant differences in 1-month postoperative ECD among the preservation-surgery time ≤3 days, 3-6 days, and >6 days groups ( F=6.201, P<0.01), with higher ECD in preservation-surgery time ≤3 days groups than in 3-6 days and >6 days groups (both P<0.01).The preoperative donor corneal ECD applied to EK was significantly higher than that applied to PKP ( t=-2.660, P<0.01).ECD at 1 month after surgery applied to PKP was significantly higher than that applied to EK ( t=4.286, P<0.01).The ECD reduction rate was 7.14% (0.01%, 17.69%) and 31.07% (22.11%, 45.86%) in PKP group and EK group, respectively, with a statistically significant difference ( Z=4.969, P<0.01).The ECD was lower in the group with dark area than in the non-dark area group before PKP, with a statistically significant difference ( t=6.789, P=0.011).There was no significant difference in ECD at 1 month after keratoplasty between the two groups ( t=0.005, P=0.945).Multivariate logistic regression model results showed that preservation-surgery time >6 days and the cause of donor death being malignant tumor were risk factors for the appearance of dark areas in donor corneal endothelium ( OR=9.038, P=0.030; OR=6.577, P=0.018).

Conclusions  The older the donor, the lower the ECD.Prolonged preservation-surgery time (>6 days) is the main factor contributing to the decline in ECD after keratolasty.Compared to PKP, there is a higher endothelial cell loss after EK.The tissue preservation-surgery time >6 days and the cause of donor death being malignant tumor are the main risk factors affecting the appearance of dark areas in the donor corneal endothelium.But the presence of physiological dark areas does not significantly influence the ECD after surgery.

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