The problem of designing and standardizing tests of scotopic vision for military purposes has claimed much attention. The light sensitivity tests (used in studies of avitaminosis) were discarded in the early 40’s in favor of form perception tests for the armed forces, but the relation of the two types of tests remains a matter of scientific interest. By means of a supplementary form-target device designed for use in the Hecht-Shlaer (research) adaptometer, data were collected on trained adult subjects for both light and form thresholds with 3° targets. Results are presented and analyzed for dark-adapted cone vision and rod vision, separately. Data are given showing the differing amounts and character of luminance necessary for cones and rods and for light versus perception of form (T) orientation. The close correspondence of these experimental findings to some results of recently released military research is shown, and the relation of these results to current visual theory on the stimulus characteristics of the retina are discussed.
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Paired replicates for light-flash sensitivity and form perception thresholds of dark-adapted rods. Values given in log I μμL, violet light below 460 mμ.a
Subj.
Date
Light
Form
Diff.
RA
12/15
2.39
3.25
0.86
RA
12/17
2.40
3.01
0.61
GB
12/3
2.98
4.38
1.40
AC
1/9
2.46
3.68
1.22
JG
11/17
3.13
4.18
1.05
JG
2/11
2.76
3.16
0.40
WEH
12/6
3.22
4.54
1.32
WEH
1/5
2.34
3.41
1.07
WEH
1/8
2.33
3.30
0.97
WEH
1/12
2.00
3.47
1.47
WEH
1/14
2.03
3.72
1.69
WEH
1/15
2.07
3.53
1.46
WEH
1/17
1.86
3.67
1.81
WEH
1/19
1.90
3.57
1.67
WEH
1/22
2.30
3.63
1.33
WEH
1/26
2.19
3.59
1.40
WEH
2/16
1.75
3.63
1.88
LK
12/1
3.14
4.14
1.00
LK
12/3
2.77
3.38
0.61
LK
12/5
2.72
3.38
0.66
LK
12/8
3.06
3.89
0.83
LK
12/12
2.37
3.05
0.68
LK
12/13
2.35
3.19
0.84
LK
12/15
2.50
3.17
0.67
LK
12/18
2.39
3.13
0.74
LK
2/19
2.50
3.22
0.72
IL
1/13
2.66
3.76
1.10
IL
1/15
2.18
3.88
1.70
EL
12/2
3.10
4.45
1.35
EL
2/3
2.44
4.17
1.73
EL
2/10
2.37
3.48
1.11
SM
12/12
2.25
3.27
1.02
SM
12/13
2.31
3.43
1.12
SM
12/15
2.08
3.35
1.27
SM
12/17
2.16
3.14
0.98
SM
12/18
2.35
3.53
1.18
MRP
2/19
2.12
3.35
1.23
LT
1/12
2.35
3.70
1.35
LT
1/14
2.06
3.39
1.33
LT
1/20
2.37
3.48
1.11
LT
2/20
2.17
3.09
0.92
BW
12/3
3.25
4.51
1.26
BW
12/5
2.89
4.54
1.65
BW
12/6
3.10
4.28
1.18
BW
12/12
2.57
3.61
1.04
BW
12/15
2.64
3.98
1.34
BW
12/17
2.55
3.51
0.96
BW
1/13
2.81
4.21
1.40
BW
1/15
2.59
4.25
1.66
BW
1/16
2.83
4.04
1.21
BW
1/26
2.73
3.84
1.11
BW
1/28
3.05
4.34
1.29
BW
1/29
2.90
4.14
1.24
BW
2/3
2.83
3.97
1.14
BW
2/5
2.94
4.04
1.10
DW
3/3
2.29
4.08
1.79
N=56 M.
2.515
3.698
1.183
N=13 M.
2.718
3.945
1.227
These 56 pairs of observations were made by 13 practiced college student subjects, as indicated, on the Hecht-Shlaer adaptometer No. 8, using Corning No. 5113 violet filter, the test fields centered 7° nasally for the right eye with 1/5-sec exposures following pre-adaptation to 1500 mL. for
to 4 min. The measurements reported here are those made 28 to 38 min after starting dark adaptation.
Table II
Paired replicates for light-flash sensitivity and form perception thresholds of dark-adapted cones with red light beyond 680 mμ and of rods with violet light below 460 mμ. Values given in log I μμL.a
These 27 double pairs of observations were made by 9 practiced college student subjects on the Hecht-Shlaer adaptometer No. 8, using Wratten No. 88 and Corning No. 5113 filters, and 3° test fields centered 7° nasally for the right eye with 1/5-sec exposures and following pre-adaptation to 1500 mL for
to 4 min. The measurements for red light were taken 12 to 30 min and for violet light 28 to 38 min after the beginning of dark adaptation.
Data secured on first trial with each of nine subjects.
Tables (2)
Table I
Paired replicates for light-flash sensitivity and form perception thresholds of dark-adapted rods. Values given in log I μμL, violet light below 460 mμ.a
Subj.
Date
Light
Form
Diff.
RA
12/15
2.39
3.25
0.86
RA
12/17
2.40
3.01
0.61
GB
12/3
2.98
4.38
1.40
AC
1/9
2.46
3.68
1.22
JG
11/17
3.13
4.18
1.05
JG
2/11
2.76
3.16
0.40
WEH
12/6
3.22
4.54
1.32
WEH
1/5
2.34
3.41
1.07
WEH
1/8
2.33
3.30
0.97
WEH
1/12
2.00
3.47
1.47
WEH
1/14
2.03
3.72
1.69
WEH
1/15
2.07
3.53
1.46
WEH
1/17
1.86
3.67
1.81
WEH
1/19
1.90
3.57
1.67
WEH
1/22
2.30
3.63
1.33
WEH
1/26
2.19
3.59
1.40
WEH
2/16
1.75
3.63
1.88
LK
12/1
3.14
4.14
1.00
LK
12/3
2.77
3.38
0.61
LK
12/5
2.72
3.38
0.66
LK
12/8
3.06
3.89
0.83
LK
12/12
2.37
3.05
0.68
LK
12/13
2.35
3.19
0.84
LK
12/15
2.50
3.17
0.67
LK
12/18
2.39
3.13
0.74
LK
2/19
2.50
3.22
0.72
IL
1/13
2.66
3.76
1.10
IL
1/15
2.18
3.88
1.70
EL
12/2
3.10
4.45
1.35
EL
2/3
2.44
4.17
1.73
EL
2/10
2.37
3.48
1.11
SM
12/12
2.25
3.27
1.02
SM
12/13
2.31
3.43
1.12
SM
12/15
2.08
3.35
1.27
SM
12/17
2.16
3.14
0.98
SM
12/18
2.35
3.53
1.18
MRP
2/19
2.12
3.35
1.23
LT
1/12
2.35
3.70
1.35
LT
1/14
2.06
3.39
1.33
LT
1/20
2.37
3.48
1.11
LT
2/20
2.17
3.09
0.92
BW
12/3
3.25
4.51
1.26
BW
12/5
2.89
4.54
1.65
BW
12/6
3.10
4.28
1.18
BW
12/12
2.57
3.61
1.04
BW
12/15
2.64
3.98
1.34
BW
12/17
2.55
3.51
0.96
BW
1/13
2.81
4.21
1.40
BW
1/15
2.59
4.25
1.66
BW
1/16
2.83
4.04
1.21
BW
1/26
2.73
3.84
1.11
BW
1/28
3.05
4.34
1.29
BW
1/29
2.90
4.14
1.24
BW
2/3
2.83
3.97
1.14
BW
2/5
2.94
4.04
1.10
DW
3/3
2.29
4.08
1.79
N=56 M.
2.515
3.698
1.183
N=13 M.
2.718
3.945
1.227
These 56 pairs of observations were made by 13 practiced college student subjects, as indicated, on the Hecht-Shlaer adaptometer No. 8, using Corning No. 5113 violet filter, the test fields centered 7° nasally for the right eye with 1/5-sec exposures following pre-adaptation to 1500 mL. for
to 4 min. The measurements reported here are those made 28 to 38 min after starting dark adaptation.
Table II
Paired replicates for light-flash sensitivity and form perception thresholds of dark-adapted cones with red light beyond 680 mμ and of rods with violet light below 460 mμ. Values given in log I μμL.a
These 27 double pairs of observations were made by 9 practiced college student subjects on the Hecht-Shlaer adaptometer No. 8, using Wratten No. 88 and Corning No. 5113 filters, and 3° test fields centered 7° nasally for the right eye with 1/5-sec exposures and following pre-adaptation to 1500 mL for
to 4 min. The measurements for red light were taken 12 to 30 min and for violet light 28 to 38 min after the beginning of dark adaptation.
Data secured on first trial with each of nine subjects.