Immune reaction after penetrating keratoplasty depending on graft size and centration

Abstract

Immune reaction (IR) after penetrating keratoplasty (PKP) is aserious complication with ahigh risk of graft failure. The aim of this study was to analyze and evaluate the risk factors for IR, in particular, the influence of graft size and centration. Atotal of 2133patients who underwent PKP between January 2009 and July 2019 were included in this retrospective study. The following endpoints were analyzed: frequency of IR, graft origin, donor and patient age, diagnosis, corneal diameter and ratio of the graft size to the recipient cornea size. In addition, the role of graft centration, with the help of distance measurements of the graft margins to the vascularized limbus at four locations, was investigated in detail. Overall, 8.25% of patients suffered from IR during the observational period. The frequency of IR was significantly correlated (p < 0.001) with the ratio of the graft size to the recipient cornea size. In addition, astatistically significant correlation was found between the occurrence of IR and asmall distance to the limbal margins in the Y‑axis (inferior and superior). In particular, the correlation coefficient was larger at the inferior limbus (p < 0.001). An IR after PKP is anot uncommon complication and is significantly related to graft size and centration. Alarge graft chosen in relation to the recipient cornea and the proximity of the graft to the vascularized limbus at the inferior and superior sites significantly correlate with the occurrence of IR. These are important risk factors for graft survival, which can be influenced by the corneal microsurgeon and could possibly be further optimized in the future.