Diagnostic performance of corneal microlayer tomography in the diagnosis of Fuchs endothelial dystrophy

Abstract

Purpose : To evaluate the utility of regional Endothelium/Descemet complex thickness (rDMT) obtained using corneal microlayer tomography technique versus regional total corneal thickness in the diagnosis of Fuchs endothelial dystrophy (FED)

Methods : 86 eyes (36 with FED, along with 50 age-matched controls) were imaged using high-definition optical coherence tomography with 6 mm radial cuts centered on the corneal vertex. Custom-made segmentation algorithm was used to generate 6 mm color-coded maps and bulls-eye maps divided into central, paracentral, and peripheral regions [fig.1]. Independent-samples T-test was performed to compare the means of central, paracentral, and peripheral DMTs and total corneal thickness between studied groups. Receiver operating characteristic curves were used to determine the accuracy of the rDMTs and regional total corneal thickness in differentiating between both groups

Results : The mean central, paracentral, and peripheral DMT was significantly thicker in FED group compared to controls with a mean difference of (7, 8, and 11µm, p<0.001) in central, paracentral, and peripheral regions, respectively. Similarly, the mean central, paracentral, and peripheral total corneal thickness was significantly thicker in FED group with a mean difference of (40, 37, and 35µm, p<0.001) in central, paracentral, and peripheral regions, respectively. The rDMTs achieved higher accuracy than total corneal thickness in differentiating Fuchs eyes from the normal ones with area under the curve (AUC) = 0.954, 0.977, and 0.990 versus 0.803, 0.807, and 0.792 for central, paracentral, and peripheral regions, respectively [fig.2]. Peripheral DMT with an optimal cut off value (OCV) of 22µm achieved the highest sensitivity 92% and specificity 96% versus 69% sensitivity and 80% specificity for central corneal thickness with an OCV of 540µm

Conclusions : Peripheral, central, and paracentral DMTs are novel signs for the diagnosis of Fuchs endothelial dystrophy with excellent accuracy in differentiating it from normal corneas

This abstract was presented at the 2019 ARVO Imaging in the Eye Conference, held in Vancouver, Canada, April 26-27, 2019.

 

Fig.1: Graph-based segmentation algorithm showing the generated color-coded maps and bulls-eye maps for the total corneal thickness (left side) and endothelium/Descemet complex thickness (right side)

 

Fig.2: Combined ROC curves of the regional corneal thickness, and Endothelium/Descemet thickness showing higher accuracy of the latter in differentiating Fuchs eyes from the normal ones