Review of Wartime Studies of Dark Adaptation, Night Vision Tests, and Related Topics (1949) / Chapter Skim
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Review of Wartime Studies of Dark Adaptation, Night Vision Tests and Related Topics
Review of Wartime Studies of Dark Adaptation, Night Vision Tests and Related Topics
Pages 10-101
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From page 10... ...
The writer would contend, however, that nothing less is worth doing: The present tests eliminate night blinds, and there is no evidence that they do, or could do, more. REVIEW OF WARTIME STUDIES OF DARK ADAPTATION, NIGHT VISION TESTS AND RELATED TOPICS William Berry INTRODUCTION *
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From page 11... ...
It was found that the heterogenous material did not readily or adequately lend itself to such treatment, due to the inherent variability in it, not only with respect to the topics covered by the individual reports, but also with respect to such details as the brightness levels of screen and target, the character and complexity of the targets or test objects, the experimental and test procedures used, and statistical methods of treating the data obtained.
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From page 12... ...
Furthermore, it became clear that something more than a patch of light as a test object was necessary if a test had to have even a modicum of meaning as an indicator of night visual ability. From this point on, the development of an amazing variety of test devices proceeded apace.
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From page 13... ...
Investigations of scotopic acuity in various •tinal regions, of the characteristics of the scotopic luminosity curve, of scotopic sensory thres>lds, of the detection of targets under conditions of low illumination, and of electrical recordings om the retina in dark adaptation are but a few examples of the varied phases of the basic re:arch. On the other hand the question whether it should be closely, remotely, or not at all as>ciated with research in the development of adequate night vision tests is a debatable one.
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From page 15... ...
709 r = .74 84 Army Night NVT-15 NVT-15 P Vision Tester r = .91 Odd-even r = .89 (Rostenberg) Test-retest r = .80 NVT-R 2 (Radium)
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From page 16... ...
90 38 Hecht-Shlaer RCN Model r = .636 108 50 Hecht-Shlaer •RCN Model (See the Abstract for statement.) 66 Hecht-Shlaer Portable Light r = .64 Form .48 24 73 Hecht-Shlaer RCN Model •r = .422 150 19 Hopkins Test r = .61 38 37 Hopkins Test (Radium)
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From page 17... ...
r = .90 .80 .89 150 74 Navy Radium Plaque (See the Abstract for statement.) 75 Navy Radium Plaque 4 Tests Test 1 Test 2 Test 3 vs vs Test 3 Test 4 vs Test 2 p = .63 .75 .69 234 77 Navy Radium Plaque "Standard "Raw score" score" Split -ha If 100
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From page 18... ...
1 Test 2 Plaque vs vs vs vs vs vs Test 2 Test 3 Test 4 Test 3 Test 4 Test 4 Tetrachoric r= .65 .66 .52 .43 .52 .47 115 104 Navy Radium Plaque (See the Abstract for statements.) 105 Navy Radium Test given at 5 feet distance Plaque 5 feet 7 feet vs distance distance 7 feet distance r = .815 .821 .729 24 106 Navy Radium Plaque (See the Abstract for data and conclusions.)
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From page 19... ...
Chi square = 7.39 16.46 16.20 27 Pensacola Significant at the 1%, or better, level 150 (Pensad) (See the Abstract for statement.)
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From page 20... ...
DATA ON INTERCORRELATIONS BETWEEN ADAPTOMETERS AND NIGHT VISION TESTERS. COEFFICIENTS CITED ARE PRODUCTAbstract MOMENT, EXCEPT WHERE OTHERWISE NOTED.
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From page 21... ...
r = .85 16 AeroMedLab Correlated SchAvMed SAM RPNVT with Portable r = .26 200 94 AeroMedLab Correlated AAF-Eastman r = .52 to .82 RPNVT with NV Tester 02 AeroMedLab Correlated Army Night Vision RPNVT with Tester ANVT-1 r = .67 32 71 Army NV Tester Correlated Army NV Tester (See the Abstract Various models with Various models for data.) .00 Army NV Tester Correlated Navy Radium Modified with Plaque Rostenberg Average of 4 Tests (Tetrachoric)
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From page 22... ...
86 Hecht-Shlaer Model 3 Correlated with SchAvMed SAM Portable (See the Abstract for statement.) 99 Hecht-Shlaer Correlated with Navy Radium Plaque r = -.67 28 66 Johnson Found.
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From page 23... ...
00 Navy Radium Plaque Correlated with Army NV Tester Modified Rostenberg (Tetrachoric) r Average of 4 Tests .565 115 03 Navy_ Radium Plaque Correlated with NavMedResInst NNMC, Bethesda (Tetrachoric)
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From page 25... ...
73- Hecht-Shlaer Correlated with Night Lookout Performance (See the Abstract for statement.) 19 Hopkins Test Correlated with Road Test r = .28 to .58 38 19 Luckiesh-Moss Contrast Card Correlated with Road Test r = .19 to .38 38 71 Luckiesh-Moss Contrast Card Correlated with Various Outdoor Tests (See the Abstract for statement.)
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From page 26... ...
74 Navy Radium Plaque Related to Night Lookout Training (See the Abstract for statement.) 91 Navy Radium Plaque Related to Night Lookout Performance (See the Abstract for statement.)
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From page 27... ...
An inability to perceive a light intensity of less than 3.5 log units at the end of 30 minutes of dark adaptation was considered to indicate deficiency in dark adaptation.
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From page 28... ...
(C) An equation for the treatment of the data in individual dark adaptation curves obtained in the standard Hecht-Shlaer adaptometer procedure was developed and its use illustrated in typical examples.
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From page 29... ...
PINSON. Dark adaptation in army air corps personnel.
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From page 30... ...
Miles concerning the use of red goggles in his studies of dark adaptation. He stated that subjects who wore them in a room lighted f with about 6 millilamberts of light intensity while reading or doing other visual work gave terminal threshold values closely similar to those obtained after adaptation in a completely dark room.
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From page 31... ...
(C) A study of the dark adaptation curves obtained from 1 subject when the test fields were violet, sextant green, jena green, red, and white, respectively.
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From page 32... ...
First, a normal dark adaptation curve for the right eye was obtained and used for comparison with the curves obtained in the subsequent tests.
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From page 33... ...
ANON. Dark adaptation study, U.S.S.
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From page 34... ...
LEE. Report on the influence of brightness of red and white preadapting lights on the course of dark adaptation for various colors of test fields, and tests of specific goggles submitted by the Medical research section.
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From page 35... ...
(O) A report of a trip by the author to Randolph Field in order to initiate studies in the School of Aviation Medicine on night vision and night vision testing, to acquaint the personnel with the methods of procedure used in studies of dark adaptation and night vision, and to accumulate data on air corps personnel which could be used for the purpose of classifying them with respect to night visual efficiency.
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From page 36... ...
(C) The apparatus, used in conjunction with a low pressure chamber in a number of studies of dark adaptation under various conditions, was described.
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From page 37... ...
The device was designed to test not only dark adaptation but also visual acuity and the rate of recovery from a moderate degree of glare effect. The test objects were letters of the Snellen type viewed through a layer of material varying in opacity from top to bottom of a drumlike structure.
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From page 38... ...
However, not much is known about the variability in its size under different levels of illumination and at different periods in the course of dark adaptation. The purpose of the investigation was to measure central scotomata with two types of scotometers, one described as a dark field and the other described as a bright field.
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From page 39... ...
Cases Dark Field: 4.3 9.2 20 4.9 3.9 22 5.2 2.0 22 Bright Field: 4.3 10.0 1 4.9 9.2 5 5.2 5.0 5 Dark adaptation thresholds were obtained from 17 subjects by means of the Hecht-Shlaer adaptometer, 3° test field. The range of the thresholds was from 3.43 to 2.2 log units with an average of approximately 2.75 log units.
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From page 40... ...
(C) Three adaptometer s were used in this investigation to ascertain the relationships between the scores obtained with each instrument, and the kind of effect specific training in night lookout had upon adaptometer scores.
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From page 41... ...
(O) A study was made of the test-retest reliability of the AAF-Eastman Night Vision Tester (model 1)
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From page 42... ...
(R) The purpose of the study was to discover if illumination of ready rooms with red light was a simpler method of shortening the time required for dark adaptation than the use of red adaptor goggles.
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From page 43... ...
The average time required to adapt to within .2 log units micromicrolamberts of the threshold to light was 6 minutes following 20 minutes exposure to the red light. This did not differ materially from the time required when red goggles were worn.
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From page 44... ...
ft
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From page 45... ...
HULBERT. Report on dark adaptation; time to become dark adapted after stimulation by various brightnesses and colors.
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From page 46... ...
When ultra-violet light of 366 wave length was used the time required to see the screen and the black objects at both 1 and 6 foot candles levels was given as 5 to 10 seconds. A comparison was made between the dark adaptation times following stimulation with equal illuminations of white tungsten light and red light, wave length 650, through a series of stimulating light levels from .1 foot candle to 1000 foot candles.
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From page 47... ...
The test field was either a light square subtending a visual angle of 9° 10' or a similar square containing a silhouette image of an airplane. Brightness values of the test field ranged from 5.75 to 2.75 log units micromicrolamberts.
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From page 48... ...
(R) To determine the effectiveness of goggles for the restoration of dark adaptation which has been lost, a study was made with 4 subjects under the following conditions: Red goggles were worn for 10 minutes and an additional 10 minutes spent in complete darkness.
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From page 49... ...
The time required to reach .2 log unit above the final threshold was 9 minutes and 2 minutes, following 45 minutes exposure while wearing the goggles. The data presented led to the conclusion that the only combination giving adequate visibility and rapid recovery of dark adaptation is that in which the goggles are worn for 45 minutes in a room brightness of 20.65 millilamberts.
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From page 50... ...
The answers given by the men were negative with respect to the classifications given them on the basis of adaptometer scores. The table below is an example of the results obtained: Classification _ "Feeling well" _ "Not feeling well" _ N _ % _ N _ % Superior 278 96.5 ' 10 3.5 Pass 340 98.1 7 1.9 Disqualified 133 97.1 4 2.9 A comparison was made between measurements of visual acuity by means of standard charts and NDRC model III adaptometer scores, or classifications made on the basis of the scores.
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From page 51... ...
Those men who obtained complete correct scores at this level were further tested at two lower levels, approximately 3.85 and 3.70 log units respectively. It was at the lowest level that the men ceased to make perfect scores as a general rule.
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From page 52... ...
The fluctuations had a periodicity of 3 to 7 minutes during the course of dark adaptation and an irregular amplitude from .05 to .25 log units. They were found in all dark adaptation thresholds below the highest levels.
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From page 53... ...
REED. Field tests of the radium plaque adaptometer.
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From page 54... ...
2 1943) and in British sources that red light has an accelerating effect on the rate of dark adaptation, and that terminal thresholds are lower after a period of exposure to red light than they are after a similar period spent in complete darkness.
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From page 55... ...
ROWLAND. The SAM portable night vision tester.
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From page 56... ...
Considerable discrepancy was noted although the largest number of the men were placed in the satisfactory or average group. For example, it was found that of 55 cases classified unsatisfactory by the AAF-Eastman adaptometer, with a 1 degree object and a brightness of 6.25 log units micromicrolamberts, 2 were classified unsatisfactory, 48 were satisfactory and 5 were superior by the SAM portable adaptometer.
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From page 57... ...
The computations were for 40 trials tests and the Spearman-Brown formula used to predict the reliabilities of the 80-trial tests, split-half, reliabilities. NVX-1 NVX-2 Test NVX-4 NVX-13 NVX-16 NVT-15 40 trials r = .85 .85 .93 80 trials r = .92 .92 .97 1st trial vs 2nd trial r = .83 .82 .92 Number of cases N = 100 312 70 .90 .95 .87 98 .90 .95 .86 71 .82 .90 .74 709 The following data have been selected as typical examples and show the relationships found between the indoor laboratory tests and the outdoor tests: (Table on p.
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From page 58... ...
to determine the predictive value of the tests with respect to the night lookout ability of the men tested. The instruments used were the Navy Radium Plaque, the Clockface adaptomer, the Smith Test of Visual-Motor Coordination, the Tufts-SDS Test of Night Vision, the Hecht-Shlaer adaptometer (RCN model)
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From page 59... ...
The chi-square technique was used to estimate the reliability of the Radium Plaque and NORC scores with these results: Radium Plaque Score in terms of per cent correct 50% 60% 80% Chi square = 24.17 31.16 33.69 NDRC Model III Cutting score per cent correct 20% 30% 50% Chi square = 7.39 16.36 16.20 All the chi squares given above were said to be values significant at the 1% or better level of confidence. In the case of the scores on the night Lookout Trainer (NLOT)
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From page 60... ...
The Radium Plaque did not show any significant relationship to night lookout performance and the NDRC model III showed a relationship to the criterion at two cutting scores. However, both were said to be poor predictors of performance.
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From page 61... ...
COMMONER. Field study of navy radium plaque adaptometer.
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From page 62... ...
The range of speed, expressed in seconds per 30 degrees of central angle, was from 12.64 to .62 with a median of 3.81. The test with the Radium Plaque Adaptometer was administered according to standard procedure including 50 presentations of the stimulus.
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From page 63... ...
Tester and the Luminous Plaque (Radium Plaque Night Vision Tester)
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From page 65... ...
Field Landolt-Ring r = .769 .709 .508 .744 Part III. Radium Plaque Night Vision Tester vs AAF and Field Tests.
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From page 66... ...
This phase of the test was added to study the value of a simple adaptation test and to demonstrate to the subjects the value of dark adaptation. The data were presented in histograms only, 6 figures.
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From page 67... ...
However, tests had a basic value in that men whose field performance was poor enough to warrant classification as "night blind" could not pass any one of them in which the statistical basis was sound. The Navy adopted the Radium Plaque Adaptometer for use only in screening the men with inferior night vision.
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From page 68... ...
The tests differed in terms of source of illumination, brightness levels used, and in the type of test object. In NVT-15 there were three 3 c.p.
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From page 69... ...
Portable Night Vision Tester and the AAF-Eastman, Model 2 could be greatly enhanced provided the size of the test object in the AAF-Eastman was increased from 1 to 2°, and the maximum brightness reduced from 6.25 to 5.7 log units. The author pointed out that the accumulated experience with the instrument on the part of the Aero Medical Laboratory staff was at variance with the conclusion and that the discrepancy indicated might be due to the difference in statistical methods used by the Aero Medical Laboratory and the School of Aviation Medicine, the latter being inadequate for the purposes intended.
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From page 71... ...
H Peckham and the results given in a report titled: "Report of five hundred subjects tested and retested for 50 trials each on the Navy Radium Plaque Adaptometer," dated March 8, 1944 and designated Appendix B in the report cited at the head of this Abstract.
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From page 72... ...
JOHNSON. The course of dark adaptation after wearing orange dark adaptor goggles.
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From page 73... ...
Only slight loss of dark adaptation occurred when red goggles were worn and the recovery time was short, viz., within 2-2j minutes. Inasmuch as orange goggles are not practical as dark adaptors or as preservers of dark adaptation another substitute for red goggles must be sought when interference with the performance of certain duties is brought about by their use.
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From page 74... ...
If the course of dark adaptation is divided into 3 sections, namely, from j to 10 minutes, from 10| to 20 minutes, and from 20j to 30 minutes, the average differences between control thresholds and experimental thresholds were .24, .21, and .17 log units respectively. The probability of such differences occurring by chance is .05, and hence the differences were said to be significant.
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From page 75... ...
One phase of the experiment was to ascertain how well the Navy Radium Plaque Adaptometer predicts night lookout performance. Data on both ESF scores and Radium Plaque scores for 63 men were available.
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From page 76... ...
of the Aero Medical Laboratory Radium Plaque night vision tester was given. The device consists of a small case, 5 3/8 x 6 3/4 x 3/4", containing a glass cell filled with radium salts.
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From page 77... ...
. The purpose of the experiment was to find a substitute for the standard Navy red goggles which would protect dark adaptation and permit color perception at the same time.
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From page 78... ...
7.5 2.0 1.0 3.0 3.5 7.5 10 minutes 8.0 2.5 1.0 3.5 4.0 13.0 15 minutes 15.0 2.5 2.0 8.5 4.5 21.0 Recovery of the original dark adaptation state was regarded as the return to the group limen or to a point within .05 log units of it. This was regarded as quite satisfactory for a laboratory situation, but may be too rigid for field requirements.
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From page 79... ...
The data are as follows: Regions of maximal acuity under different intensities (log units) rho = .46 .93 .93 .79 .81 rho = .70 .85 .88 .77 .80 0° fixation.
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From page 80... ...
S Navy radium plaque adaptometer scores.
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From page 81... ...
In the second, 5 subjects gazed at the sky which varied from 3,500 to 16,000 millilamberts for periods of 2 to 35 minutes. For comparison, dark adaptation curves w*
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From page 82... ...
morning, afternoon and next morning for the indoor group, and following 1 hour of dark adaptation in each case, showed that the threshold was raised by .14 log units due to sunlight and that the effect did not disappear until some time later in the night. Two conclusions were stated and their military significance discussed in some detail with illustrative examples: 1.
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From page 83... ...
I The experiment was designed to study the effect on Standard Navy Radium Plaque Adaptometer scores of variations in the distance from the instrument to the subjects being tested.
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From page 84... ...
to test the night vision ability of 124 men by means of the Navy Radium Plaque at several distances, (2) to determine the reliability of the "distance method" and the relationship between RPA scores so obtained and threshold scores obtained by the Hecht-Shlaer Adaptometer.
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From page 85... ...
No significant differences were 'ound between the original distribution of the scores and the distribution of the scores of this jroup. On the basis of the results it was stated that each of the distances used in the test with the Radium Plaque Adaptometer would have certain advantages.
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From page 86... ...
(O) An investigation of the test reliability and ease of operation of the modified Rostenberg and the Navy Radium Plaque Adaptometers was made.
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From page 87... ...
S » 115 Navy Radium Plaque Modified Rostenberg :*
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From page 88... ...
the construction of the adaptometer, and (b) the comparison of the performance of subjects when tested by the instrument and two other devices, namely, the Navy Radium Plaque Adaptometer and the Modified Rostenberg apparatus.
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From page 90... ...
In a discussion it is pointed out that ft test of the Radium Plaque type must be based on the statistical properties of small sample*
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From page 91... ...
The third device was the Navy Radium Plaque Adaptometer. Twentyfour subjects were given tests and retests with each device.
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From page 92... ...
Chi square test of reliability of RPA Pass/Fail classification Chi square = 458; p = less than .00001 (2) 5% tetrachoric r = .95 1% tetrachoric r = .91 The results were said to indicate that the pass/fail categorization preferred by the RPA test of night vision is highly reliable.
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From page 93... ...
Chi square tests of homogeneity on the percentages of men passing and failing the tests in each group were computed. A condensation of the table shows: Chi square tests of homogeneity of three populations.
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From page 95... ...
97,99,100,103,104,105,106 Navy Tele silhouette 50 OSRD-NDRC 11,16,27,31,35,46,55,56,57,58, NDRC, various models 66,73 Pensacola, Pensad 27 Purkinje Test 73
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From page 97... ...
on the course of Goggles, use of Independence of one eye Night Look Out Duties Tests Training Night Vision Adaptacuity Age factor Effect of sugar Fluctuations of seeing Foveal visual acuity Frequency of seeing 50 30,40,61,68,70,78,79,86 35,38,46 79 73 73 5,9,24 44,50 2,5,8,11.12,16,17.26.27,32, 33.37,40,55,59.61,71,73,76, 78.84.94,100,101,103 28 48,54,72,88,92,95 10.15.22,42,49,51,62,67,98 10,15,22,42,54,62,88,92,95 18 9,57,73 73,74,91 38 33,38 1.2,7.9,21,23.29 9,20,24 23,39,62,90 81,85.96 39,46,52,62,69.72.104
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From page 99... ...
96 TRlL i LD • Non-visual factors 2,21,93 Perception; Light, flash 4,11,13,16,21,23,34,39,53,69 Perception; Form, object 11,13,16,17,21,23,34,39,53,77 Perception; Discrimination 53 Peripheral visual acuity 82,85,96 Racial differences 20,24,29 Scoptopic acuity for motion perception 77 Scotomata 23.36 Selection of personnel with superior night vision 57,59,99 Thresholds 1,2,5,9,10,16,21,23,36,39,42, 46,51,52,53,69,88,95,98 Trainer 99 Training 23,82,97 Night Vision Tests Classification on basis of scores 5,9,25,46,57,58,63,70,77,83, 86,87,94.99.106 Design and use of outdoor night vision tests 19,27,71,73,78,84,86,91,99 Distribution of scores 9,24,44,46,82,99,100,103,104 Effect of learning 9,41,46,64,75,82,87,97 Fixation points, use of 28,35,48,96,100 Methods of scoring 4,5,6,46,58,65,77,83,86,87,89, 90,93,99,100,104 Variability 7,35,75,93 Scotometers 36,105
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