Endothelial Image Quality After Descemet Stripping With Endothelial Keratoplasty: A Comparison of Three Microscopy Techniques

Abstract

To determine corneal endothelial image quality after descemet stripping with endothelial keratoplasty (DSEK) as recorded by three different microscopy techniques: noncontact specular microscopy, noncontact confocal microscopy, and contact confocal microscopy. The corneal endothelium of 52 eyes after DSEK and 20 normal eyes was photographed by the three microscopy techniques during a single encounter. Image quality was graded by two masked observers according to the proportion of countable contiguous cells visible in the image; disagreements in grading were adjudicated by a third observer. Endothelial cell density was compared among the three techniques. After DSEK, image quality was better with contact confocal microscopy than with noncontact confocal microscopy (P = 0.01) and better with noncontact confocal microscopy than with noncontact specular microscopy (P < 0.001). With noncontact specular microscopy, 42% of images after DSEK were uncountable. In normal corneas, all images were countable, and although image quality was better with contact confocal microscopy than with noncontact confocal (P = 0.03) and noncontact specular (P < 0.001) microscopy, the difference was not clinically important. For countable images, the mean differences in endothelial cell density between microscopy methods were close to zero after DSEK and in normal corneas. Confocal optics enable better image quality of the corneal endothelium in corneas with high backscatter, such as those after DSEK. When images were countable, there was a good agreement for endothelial cell density measured by the three microscopy techniques.