Abstract
Purpose: :
To determine changes in anterior corneal cells in Fuchs endothelial dystrophy before and after Descemet stripping endothelial keratoplasty (DSEK).
Methods: :
Forty-nine eyes of 42 patients (ages 41 to 87 years; mean, 67 years) with Fuchs dystrophy were examined before and at 1, 2, and 3 years after DSEK. None of the corneas were vascularized or had pronounced subepithelial fibrosis by slit-lamp examination. Keratocyte density was determined in 5 stromal layers by using confocal microscopy (ConfoScan 4, Nidek) and a custom image analysis program validated for normal corneas. Because corneas with Fuchs dystrophy were abnormal, all images analyzed by the program were reviewed and corrected by an experienced observer (SVP). Keratocyte density in corneas before DSEK was adjusted for stromal edema, which was determined from stromal thickness at 1 year after DSEK, and assuming uniform swelling of the cornea. Keratocyte density before DSEK was compared to that of 34 normal corneas of 34 younger subjects after adjusting all densities for the age-related physiologic decrease in density of 0.45% per year, and keratocyte density after DSEK was compared to that before DSEK. Densities were compared by using generalized estimating equation models to account for possible correlation between fellow eyes of the same subject. The presence of abnormal subepithelial cells, presumed to be fibroblasts, was recorded before and after DSEK.
Results: :
Keratocyte density, adjusted for age 65 years, in the anterior 10% of the stroma in Fuchs dystrophy (22,110 ± 6,385 cells/mm3, mean ± SD, n=41) was lower than that of normal corneas (27,894 ± 4,072 cells/mm3, n=34, p<0.001), whereas there were no differences in densities between Fuchs and normal in the other layers of the stroma. Keratocyte density in the anterior 10% of the stroma before DSEK (22,030 ± 6,479 cells/mm3, adjusted for stromal edema) remained unchanged through 3 years after DSEK (21,715 ± 5,743 cells/mm3, n=18, p=0.53). Subepithelial fibroblasts, which had bright nuclei and often formed a reticular network deep to the basal epithelial cells, were visible in 33 of the 49 eyes (67%) in at least one examination through 3 years. Preoperative corneal thickness when subepithelial fibroblasts were and were not visible was 649 ± 45 μm and 671 ± 57 μm respectively (p=0.74).
Conclusions: :
Anterior keratocyte density in Fuchs dystrophy is lower than normal and does not recover through 3 years after restoration of endothelial function. Subepithelial fibroblasts are present in most corneas with Fuchs dystrophy requiring DSEK, even in cases with mild edema and in the absence of clinically obvious subepithelial fibrosis preoperatively.
Keywords: cornea: stroma and keratocytes • transplantation • cornea: endothelium