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K. M. Kittleson, S. V. Patel, J. W. McLaren, K. H. Baratz, W. M. Bourne; Keratocyte Density: Deep Lamellar Endothelial Keratoplasty vs. Penetrating Keratoplasty. Invest. Ophthalmol. Vis. Sci. 2008;49(13):1969.
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© ARVO (1962-2015); The Authors (2016-present)
To compare keratocyte density in the anterior stroma during the first two years after deep lamellar endothelial keratoplasty (DLEK, native anterior stroma) and penetrating keratoplasty (PK, transplanted anterior stroma) to keratocyte density in normal corneas.
In this randomized, prospective trial 13 eyes received DLEK and 15 eyes received PK. Corneas were examined by confocal microscopy (Tandem Scanning, Reston, VA) before surgery, and at 1, 3, 6, 12 and 24 months after surgery. Keratocyte density was determined in layers represented by 0-10%, 11-33%, and 34-66% of the stromal depth. Only frames anterior to the graft-host interface were studied in DLEK patients (the interface obscured cells posterior to the interface). Densities in each layer were compared between patients after DLEK and PK at each examination and to 40 normal corneas. Significances of differences were determined by using Generalized Estimating equation models with Bonferroni adjustment for multiple comparisons. Minimum detectable differences (MDD) were calculated by assuming α=0.05/6=0.0083 and β=0.20.
Before surgery, mean cell densities in the anterior 10% of stroma in DLEK (32,972 ± 7,519 cells/mm3, n=10) and PK (25,657 ± 7,878 cells/mm3, n=11) corneas were significantly lower than in the same region of normal untreated corneas (44,201 ± 8,240 cells/mm3, n=40, p<0.001). After DLEK, density in this layer remained below normal to 24 months (32,357 ± 5,916 cells/mm3, n=6, p≤0.001). One month after PK, cell density in this layer (38,045 ± 8,105 cells/mm3, n=14) was not significantly different from normal (p=0.30, MDD=9,200 cells/mm3), although at 3, 12, and 24 months it was below normal density (p<0.001) and by 24 months was 33,318 ± 10,840 cells/mm3 (n=12). Cell densities in the 2 layers between 11 % and 66% of stromal thickness were not significantly different from normal at any time after DLEK (mean MDD=6,825 cells/mm3) or after PK (mean MDD=6,267 cells/mm3), except at 12 months, 34-66% (p=0.006). Cell densities in all three layers at each examination were not significantly different between corneas treated by DLEK and PK (mean MDD=10,200 cells/mm3).
During the first two years after transplant, cell densities in the anterior two thirds of the stroma are not significantly different between native stroma (after DLEK) and transplanted stroma (after PK). Two years after both procedures, cell densities in the anterior 10% of stroma remain below densities in a similar region of normal untreated corneas.
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