DICOM PS3.17 2019a - Explanatory Information

RR.2.4 Traditional Charts

The Traditional charts used in clinical practice are not standardized; they have an irregular progression of letter sizes and a variable number of characters per line. Measurement accuracy may further suffer from hidden errors that cannot be captured by any recording device, such as an inconsistent, non-standardized protocol, inaccurate viewing distance, inaccurate projector adjustment and contrast loss from room illumination. Therefore, the difference between two routine clinical measurements should not be considered significant, unless it exceeds 5 rows in the table (1 line on an ETDRS chart).

Table RR-1 contains many blank lines to make the vertical scale consistent with that used in Table RR-2. Notations within the same gray band are interchangeable for routine clinical use, since their differences are small compared to the clinical variability, which is typically in the order of 5 rows (1 ETDRS line).

Table RR-1. Reference Table for Use with Traditional Charts

DICOM

Notations for Clinical Use with Traditional Charts

Scales for statistics and graphical displays

Decimal Visual Acuity

Traditional scales

Linear Scales

Decimal

US

6 m

LogMAR

VAS

2.00 E+00

2.0

20/10

6/3

-0.30

115

1.91 E+00

-0.28

114

1.82 E+00

-0.26

113

1.74 E+00

-0.24

112

1.66 E+00

-0.22

111

1.60 E+00

1.6

20/12.5

6/3.8

-0.20

110

1.50 E+00

1.5

20/13

6/4

-0.18

109

1.45 E+00

-0.16

108

1.38 E+00

-0.14

107

1.30 E+00

1.3

20/15

6/4.5

-0.12

106

1.25 E+00

1.25

20/16

6/4.8

-0.10

105

1.20 E+00

1.2

20/17

6/5

-0.08

104

1.15 E+00

-0.06

103

1.10 E+00

1.1

20/18

6/5.5

-0.04

102

1.05 E+00

-0.02

101

1.00 E+00

1.0

20/20

6/6

0

100

9.55 E-01

0.02

99

9.00 E-01

0.9

20/22

6/66

0.04

98

8.70 E-01

0.06

97

8.30 E-01

0.08

96

8.00 E-01

0.8

20/25

6/7.5

0.10

95

7.50 E-01

0.75

20/26

6/8

0.12

94

7.20 E-01

0.14

93

7.00 E-01

0.7

20/28

6/8.7

0.16

92

6.60 E-01

0.66

20/30

6/9

0.18

91

6.30 E-01

0.63

20/32

6/9.5

0.20

90

6.00 E-01

0.6

20/33

6/10

0.22

89

5.75 E-01

0.24

88

5.50 E-01

0.26

87

5.25 E-01

0.28

86

5.00 E-01

0.5

20/40

6/12

0.30

85

4.80 E-01

0.32

84

4.57 E-01

0.34

83

4.37 E-01

0.36

82

4.17 E-01

0.38

81

4.00 E-01

0.4

20/50

6/15

0.40

80

3.80 E-01

0.42

79

3.60 E-01

0.44

78

3.50 E-01

0.46

77

3.33 E-01

0.33

20/60

6/18

0.48

76

3.20 E-01

0.32

20/63

6/19

0.50

75

3.00 E-01

0.3

20/66

6/20

0.52

74

2.90 E-01

0.28

20/70

6/21

0.54

73

2.75 E-01

0.56

72

2.63 E-01

0.58

71

2.50 E-01

0.25

20/80

6/24

0.60

70

2.40 E-01

0.62

69

2.30 E-01

0.64

68

2.20 E-01

0.66

67

2.10 E-01

0.68

66

2.00 E-01

0.2

20/100

6/30

0.70

65

1.90 E-01

0.72

64

1.82 E-01

0.74

63

1.74 E-01

0.76

62

1.66 E-01

0.17

20/120

6/36

0.78

61

1.60 E-01

0.16

20/125

6/38

0.80

60

1.50 E-01

0.15

20/130

6/40

0.82

59

1.45 E-01

0.84

58

1.38 E-01

0.86

57

1.30 E-01

0.13

20/150

6/45

0.88

56

1.25 E-01

0.125

20/160

6/48

0.90

55

1.20 E-01

0.12

20/170

6/50

0.92

54

1.15 E-01

0.94

53

1.10 E-01

0.96

52

1.05 E-01

0.98

51

1.00 E-01

0.1

20/200

6/60

1.00

50

9.55 E-02

1.02

49

9.00 E-02

1.04

48

8.70 E-02

1.06

47

8.30 E-02

0.083

20/240

6/72

1.08

46

8.00 E-02

0.08

20/250

6/75

1.10

45

7.50 E-02

1.12

44

7.20 E-02

1.14

43

7.00 E-02

1.16

42

6.60 E-02

0.065

20/300

6/90

1.18

41

6.30 E-02

0.063

20/320

6/95

1.20

40

6.00 E-02

0.06

20/330

6/100

1.22

39

5.75 E-02

1.24

38

5.50 E-02

1.26

37

5.25 E-02

1.28

36

5.00 E-02

0.05

20/400

6/120

1.30

35

4.80 E-02

1.32

34

4.60 E-02

1.34

33

4.40 E-02

1.36

32

4.20 E-02

1.38

31

4.00 E-02

0.04

20/500

6/150

1.40

30

3.80 E-02

1.42

29

3.60 E-02

1.44

28

3.50 E-02

1.46

27

3.33 E-02

1.48

26

3.20 E-02

0.032

20/630

6/190

1.50

25

3.02 E-02

0.03

20/650

6/200

1.52

24

2.90 E-02

1.54

23

2.75 E-02

1.56

22

2.63 E-02

1.58

21

2.50 E-02

0.025

20/800

6/240

1.60

20

2.40 E-02

1.62

19

2.30 E-02

1.64

18

2.20 E-02

1.66

17

2.10 E-02

1.68

16

2.00 E-02

0.02

20/1000

6/300

1.70

15

1.90 E-02

1.72

14

1.82 E-02

1.74

13

1.74 E-02

1.76

12

1.66 E-02

1.78

11

1.60 E-02

0.016

20/1250

6/380

1.80

10

1.50 E-02

0.015

20/1300

6/400

1.82

9

1.45 E-02

1.84

8

1.38 E-02

1.86

7

1.30 E-02

1.88

6

1.25 E-02

0.0125

20/1600

6/480

1.90

5

1.20 E-02

1.92

4

1.15 E-02

1.94

3

1.10 E-02

1.96

2

1.05 E-02

1.98

1

1.00 E-02

0.01

20/2000

6/600

2.00

0


DICOM PS3.17 2019a - Explanatory Information