Table 2 Descriptive statistics and repeatability of measurements on Day 0 and Day 3 in healthy controls.

From: The intra- and inter-day repeatability of corneal densitometry measurements in subjects with keratoconus and in healthy controls

Variable

Day

Mean (SD)a

Min‒Max

Sw (95% CI)

CV%

Repeatability

ICC (95% CI)

0‒2 mm

 Anterior

0

22.6 (4.4)

(16.1‒29.4)

0.40 (0.34‒0.46)

1.78

1.11

0.99 (0.98‒1.00)

3

23.0 (4.1)

(17.3‒29.3)

0.29 (0.25‒0.34)

1.26

0.82

0.99 (0.99‒1.00)

 Middle

0

14.3 (2.5)

(10.6‒18.3)

0.25 (0.21‒0.29)

1.75

0.70

0.99 (0.98‒0.99)

3

14.4 (2.3)

(11.7‒18.0)

0.24 (0.21‒0.28)

1.67

0.68

0.99 (0.98‒0.99)

 Posterior

0

11.8 (1.4)

(9.4‒13.9)

0.39 (0.33‒0.46)

3.30

1.09

0.93 (0.87‒0.96)

3

11.9 (1.3)

(10.1‒14.1)

0.34 (0.29‒0.39)

2.86

0.94

0.93 (0.89‒0.97)

 Total

0

16.2 (2.7)

(11.9‒20.5)

0.24 (0.21‒0.28)

1.48

0.68

0.99 (0.99‒1.00)

3

16.4 (2.5)

(13.1‒20.4)

0.23 (0.20‒0.27)

1.40

0.64

0.99 (0.98‒1.00)

2‒6 mm

 Anterior

0

20.3 (3.9)

(14.5‒25.9)

0.20 (0.17‒0.23)

0.99

0.55

1.00 (1.00‒1.00)

3

20.7 (3.6)

(15.9‒25.7)

0.48 (0.40‒0.55)

2.32

1.32

0.98 (0.97‒0.99)

 Middle

0

12.9 (2.1)

(9.9‒15.8)

0.13 (0.11‒0.16)

1.01

0.37

1.00 (0.99‒1.00)

3

13.1 (2.0)

(10.8‒15.7)

0.32 (0.27‒0.37)

2.44

0.89

0.97 (0.95‒0.99)

 Posterior

0

11.0 (1.3)

(9.0‒13.7)

0.30 (0.26‒0.35)

2.73

0.84

0.95 (0.91‒0.97)

3

11.1 (1.2)

(9.6‒14.0)

0.39 (0.33‒0.46)

3.51

1.09

0.91 (0.84‒0.95)

 Total

0

14.8 (2.4)

(11.2‒18.1)

0.17 (0.14‒0.19)

1.15

0.46

1.00 (0.99‒1.00)

3

15.0 (2.2)

(12.2‒18.1)

0.36 (0.30‒0.42)

2.40

1.00

0.97 (0.95‒0.99)

6‒10 mm

 Anterior

0

18.9 (3.9)

(13.6‒28.6)

1.01 (0.85‒1.17)

5.35

2.79

0.94 (0.89‒0.97)

3

19.1 (3.9)

(14.2‒29.9)

0.52 (0.43‒0.60)

2.72

1.43

0.98 (0.97‒0.99)

 Middle

0

13.2 (2.5)

(9.4‒19.7)

0.41 (0.35‒0.48)

3.11

1.15

0.97 (0.95‒0.99)

3

13.3 (2.5)

(10.3‒20.8)

0.29 (0.24‒0.34)

2.18

0.81

0.99 (0.98‒0.99)

 Posterior

0

12.3 (2.1)

(9.0‒17.7)

0.31 (0.26‒0.36)

2.52

0.87

0.98 (0.96‒0.99)

3

12.4 (2.1)

(9.9‒18.6)

0.28 (0.23‒0.32)

2.26

0.77

0.98 (0.97‒0.99)

 Total

0

14.8 (2.8)

(10.7‒22.0)

0.56 (0.47‒0.64)

3.78

1.54

0.96 (0.93‒0.98)

3

14.9 (2.8)

(11.6‒23.1)

0.33 (0.28‒0.38)

2.21

0.92

0.99 (0.97‒0.99)

10‒12 mm

 Anterior

0

28.0 (7.7)

(15.2‒49.3)

1.65 (1.38‒1.91)

5.89

4.57

0.96 (0.92‒0.98)

3

27.2 (7.9)

(17.8‒47.0)

1.49 (1.25‒1.73)

5.48

4.13

0.97 (0.94‒0.98)

 Middle

0

18.8 (3.9)

(12.3‒28.4)

0.70 (0.59‒0.82)

3.72

1.95

0.97 (0.94‒0.98)

3

18.4 (4.0)

(13.1‒28.0)

0.65 (0.55‒0.76)

3.53

1.81

0.97 (0.95‒0.99)

 Posterior

0

16.1 (3.6)

(10.6‒25.4)

0.57 (0.48‒0.66)

3.54

1.58

0.98 (0.96‒0.99)

3

16.0 (3.6)

(10.9‒25.5)

0.59 (0.49‒0.68)

3.69

1.63

0.97 (0.95‒0.99)

 Total

0

21.0 (4.6)

(12.7‒33.9)

0.91 (0.76‒1.05)

4.33

2.52

0.96 (0.93‒0.98)

3

20.4 (4.7)

(14.5‒33.0)

1.31 (1.10‒1.51)

6.42

3.62

0.93 (0.87‒0.96)

Total

 Anterior

0

21.5 (4.1)

(15.4‒30.0)

0.34 (0.28‒0.39)

1.58

0.93

0.99 (0.99‒1.00)

3

21.6 (3.9)

(16.4‒30.2)

0.37 (0.31‒0.43)

1.71

1.02

0.99 (0.98‒1.00)

 Middle

0

14.2 (2.4)

(10.4‒18.9)

0.18 (0.15‒0.20)

1.27

0.49

0.99 (0.99‒1.00)

3

14.4 (2.4)

(11.3‒19.4)

0.78 (0.66‒0.91)

5.42

2.17

0.90 (0.84‒0.95)

 Posterior

0

12.4 (1.9)

(9.4‒16.4)

0.30 (0.26‒0.35)

2.42

0.84

0.97 (0.95‒0.99)

3

12.6 (1.9)

(10.3‒17.0)

0.85 (0.71‒0.98)

6.74

2.35

0.83 (0.72‒0.91)

 Total

0

16.0 (2.7)

(11.7‒21.8)

0.21 (0.17‒0.24)

1.31

0.58

0.99 (0.99‒1.00)

3

16.2 (2.7)

(12.9‒22.2)

0.74 (0.62‒0.85)

4.57

2.04

0.93 (0.88‒0.96)

  1. aSubject mean. The values are presented in greyscale units. Standard deviation (SD), Sw (Within-subject standard deviation, CI (confidence intervals), CV% (coefficient of variation), ICC (Intraclass correlation coefficient).
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