Purpose : To evaluate the utility of regional Endothelium/Descemet’s complex (En/DM) thickness (rDMT) in the diagnosis of active corneal graft rejection.

Methods : Thirty-six eyes (24 corneal grafts; 12 clear grafts and 12 with active rejection, along with 12 age-matched control eyes) were imaged using high-definition optical coherence tomography (HD-OCT; Envisu R2210, Bioptigen, Buffalo Grove, IL, USA) with 6 mm radial cuts centered on the corneal vertex. Custom-made segmentation algorithm was used to segment the En/DM, and 6 mm bullseye maps were created and divided into three regions; central, paracentral and peripheral (Fig. 1). The mean thickness of each region was calculated. One-way ANOVA with post-hoc comparisons were performed to compare the means of central, paracentral, and peripheral rDMTs between the three groups. Receiver operating characteristic curves were generated to determine the sensitivity and specificity of the central, paracentral, and peripheral rDMTs in differentiating between the studied groups (Fig. 2).

Results : The mean central rDMTs for the control, clear, and active rejection groups were (10, 12, and 28 µm, respectively), the mean paracentral rDMTs were (11,16, and 29 µm, respectively), and the mean peripheral rDMTs were (14, 19, and 37 µm, respectively). The mean central, paracentral, and peripheral rDMTs were significantly higher in the active rejection group than both the control, and clear groups (p