Electron microscopic changes in Descemet,s Membrane(DM) in Pseudophakic bullous keratopathy and Fuchs endothelial dystrophy

Abstract

Purpose: To elucidate ultra-structural changes of the DM and endothelial cells in Fuch's Endothelial corneal Dystrophy (FECD) and Pseudophakic Bullous Keratoplasty (PKB) by scanning electron microscopy.
Methods: Descement's membrane from 8 patients were collected following DSEK performed for Fuch's endothelial Dystrophy in 3 patients and Pseudophakic Bullous keratopathy in 5 patients. Thin sections were prepared which then studied by Transmission Electron Microscopy.
Results: In FECD the DM was thickened with excrescence in all 3 cases and composed of 4 layers, though these 4 layers were not present in one FECD specimen. In FECD stripping specimen, we observed that the endothelium was markedly attenuated, especially over the excresences, to atrophic in our 6 specimens. exrescences are continuous with the third layer. Endothelial cells were completely degenerated in 2 specimens of PBK. In FECD, HCEC were thinned out, almost unnoticeable over the nodules. No nodules seen in PBK.
Conclusion: Fibroblast like morphological changes occur in endothelial cells in both FECD and PBK with increased rough endoplasmic reticulum, cytoplasmic filaments, lysosomes and increased degenerative changes like swollen mitochondria, however these changes are more marked in FECD than in PBK. DM sticks abnormal posterior banded layer consistently in FECD but can also be found in PBK. DM thickening is more marked in FECD than in PBK. Features that are seen in FECD stroma are presence of lipid keratopathy, melanin granules separating it from PBK.