Abstract
Purpose: :
Keratocyte density is decreased in corneas after penetrating keratoplasty. In this study, we determined keratocyte density after Descemet-stripping with endothelial keratoplasty (DSEK) for Fuchs’ endothelial dystrophy.
Methods: :
We examined 37 corneas (34 patients) at 6 months and 26 corneas (21 patients) at 12 months after DSEK by confocal microscopy (ConfoScan 4 with z-ring adapter, Nidek Technologies). Preoperative diagnosis was Fuchs’ dystrophy in all cases and mean age of the patients was 67 years (42 to 85 years). Keratocyte density was determined in 5 host stromal layers and 2 donor stromal layers from confocal images by using an automated cell counting program. Cell density in each layer was compared to density in similar layers of 36 normal corneas (18 subjects; mean age, 43 years; 29 to 55 years) by using generalized estimating equation models to account for possible correlation between fellow eyes of the same subject.
Results: :
Accurate cell density measurements were not possible in the anterior 10% of the host stroma in DSEK corneas because of anterior corneal haze. Densities in the remainder of the host stroma at 6 months (mid-stroma, 21,273 ± 4,931 cells/mm3) and 12 months (mid stroma, 20,996 ± 3,785 cells/mm3) after DSEK were lower than in the same layers of control corneas (mid-stroma, 24,760 ± 3,783 cells/mm3; p≤0.02). Host stromal densities did not differ between 6 and 12 months after DSEK (p≥0.35). Donor cell densities at 6 months after DSEK (anterior donor, 16,782 ± 6,499 cells/mm3) were lower than corresponding layers of control corneas (23,649 ± 4,339 cells/mm3; p<0.001). After adjusting for the physiologic rate of keratocyte loss of 0.45% per year, cell densities were not different between the DSEK host stroma and control stroma (6 months, p=0.36; 12 months, p=0.18).
Conclusions: :
Host keratocyte density after DSEK is lower than in younger normal corneas, and this difference can be explained by the age-related physiologic keratocyte loss that we have previously described. Donor keratocyte density is lower than normal, a characteristic similar to that previously found in donor corneas after penetrating keratoplasty.
Keywords: cornea: clinical science • cornea: stroma and keratocytes • transplantation