Table 6 The required aliased character x-height and the necessary vertical pixel density of the displaying screen for performing the near-vision test at viewing distance D = 40cm

1.3

6/120

11.56

11.33

2.11

10.99

1.2

6/95

9.18

9.99

2.19

13.83

1.1

6/76

7.30

7.19

1.50

17.40

1.0

6/60

5.80

5.75

0.79

21.90

0.9

6/48

4.61

4.50

2.43

27.54

0.8

6/38

3.66

3.78

3.19

34.66

0.7

6/30

2.91

2.70

7.21

43.64

0.6

6/24

2.3

2.16

6.55

54.98

0.5

6/20

1.84

1.80

1.96

69.13

0.4

6/15

1.46

1.44

1.26

86.98

0.3

6/12

1.16

1.08

6.77

109.48

0.2

6/10

0.92

0.90

2.19

138.37

Too small character for useful display with the specific screen

0.1

6/8

0.73

N/A

N/A

175.17

0.0

6/6

0.58

N/A

N/A

218.97

-0.1

6/4.8

0.46

N/A

N/A

273.71

-0.2

6/3.8

0.37

N/A

N/A

346.19

-0.3

6/3

0.29

N/A

N/A

437.93