Visualization of Ex Vivo Porcine Corneal Endothelial Cells Using Smartphone-Assisted Specular Reflection With Slit-Lamp Biomicroscopy.

Abstract

OBJECTIVE: To visualize corneal endothelial cells in enucleated porcine eyes using slit-lamp imaging with a mobile smartphone (SLiM), determine optimal illumination conditions, and explore agreement between SLiM and vital dye stained imaging. ANIMALS STUDIED: Twelve enucleated porcine eyes. PROCEDURES: Corneal endothelium imaging conditions of the SLiM were varied by adjusting the angle between the illumination unit and microscope unit (AIM), slit-width (SW), and light intensity (LI). Subsequently, the corneal endothelium was stained with a vital dye as a reference. SLiM image quality was graded to identify optimal conditions. Endothelial cell density (ECD), percentage of hexagonal cells (HEX), and the coefficient of variation in cell area (CV) were compared between SLiM and stained images. RESULTS: The cumulative link mixed model showed that AIM, SW, and LI significantly influenced the image quality. Image quality grades were significantly higher with 60&#xb0; AIM than with 40&#xb0; or 80&#xb0; AIM (p&#x2009;<&#x2009;0.001) and lower with 7&#x2009;mm SW than with 3 or 5&#x2009;mm (p&#x2009;<&#x2009;0.001). High and medium LI produced higher grades than full LI (p&#x2009;<&#x2009;0.05), whereas Low LI significantly reduced image quality (p&#x2009;<&#x2009;0.001). SW and LI had a statistically significant interaction effect on image quality grades. Best-performing conditions were 60&#xb0; AIM, 3&#x2009;mm SW, and high LI. ECD, HEX, and CV values obtained from SLiM and vital dye stained images were comparable in three selected eyes. CONCLUSIONS: SLiM was feasible for imaging porcine corneal endothelial cells, with optimal image quality achieved under specific illumination conditions.