The Use of Digital Microscopy to Compare the Thicknesses of Normal Corneas and Ex Vivo Rejected Corneal Grafts with a Focus on the Descemet’s Membrane
Table 3
Internal validation: comparison between corneal measurements obtained from manual microscopy only and digital microscopy on 10 normal corneas stained with periodic acid-Schiff (PAS).
Corneal measurements
Manual microscopy
Digital microscopy
% Difference
CASE 1
Total cornea (μm, 10x)
560.00
560.00
0.00
Epithelium (μm, 40x)
23.00
22.91
−0.39
Descemet’s membrane (μm, 40x)
7.50
7.50
0.00
CASE 2
Total cornea (μm, 10x)
570.00
570.00
0.00
Epithelium (μm, 40x)
38.75
38.78
0.08
Descemet’s membrane (μm, 40x)
5.27
5.27
0.00
CASE 3
Total cornea (μm, 10x)
590.00
590.00
0.00
Epithelium (μm, 40x)
48.50
48.49
−0.02
Descemet’s membrane (μm, 40x)
10.00
10.04
0.40
CASE 4
Total cornea (μm, 10x)
690.00
690.00
0.00
Epithelium (μm, 40x)
32.25
32.25
0.00
Descemet’s membrane (μm, 40x)
9.25
9.25
0.00
CASE 5
Total cornea (μm, 10x)
680.00
680.00
0.00
Epithelium (μm, 40x)
36.30
36.31
0.03
Descemet’s membrane (μm, 40x)
10.20
10.21
0.10
CASE 6
Total cornea (μm, 10x)
660.00
660.00
0.00
Epithelium (μm, 40x)
41.80
41.86
0.14
Descemet’s membrane (μm, 40x)
8.30
8.31
0.12
CASE 7
Total cornea (μm, 10x)
520.00
520.00
0.00
Epithelium (μm, 40x)
41.40
41.44
0.10
Descemet’s membrane (μm, 40x)
5.60
5.61
0.18
CASE 8
Total cornea (μm, 10x)
560.00
560.00
0.00
Epithelium (μm, 40x)
38.60
38.59
−0.03
Descemet’s membrane (μm, 40x)
7.61
7.61
0.00
CASE 9
Total cornea (μm, 10x)
620.00
620.00
0.00
Epithelium (μm, 40x)
35.33
35.34
0.03
Descemet’s membrane (μm, 40x)
7.26
7.26
0.00
CASE 10
Total cornea (μm, 10x)
700.00
700.00
0.00
Epithelium (μm, 40x)
30.01
30.03
0.07
Descemet’s membrane (μm, 40x)
9.58
9.58
0.00
MEAN OF 10 CASES
value
Cornea total (μm, 10x, mean ± SD)
615.000 (±64.000)
619.000 (±64.000)
0.885
Epithelium (μm, 40x, mean ± SD)
37.295 (±5.802)
36.600 (±7.090)
0.813
Descemet’s membrane (μm, 40x, mean ± SD)
8.265 (±1.786)
8.066 (±1.737)
0.804
μm = Micrometer; 10x, 40x = Microscope magnification; SD = Standard deviation. The Kolmogorov–Smirnov test was used to test the equality of probability distribution, whereas the comparisons of two independent variables were performed using Student’s t-test for continuous variables. Levene’s test was used to analyze homogeneity.
