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OCR for page 33
DARK ADAPTATION
AND NIGHT VISION
OCR for page 34
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Review of Wartime Studies of Dark Adaptation, Night
Vision Tests, and Related Topics
William Berry
1949
.
The initial plan of this project was to summarize the articles prepared
under the stimulation of military requirements during the years 1941-1946.
It was assumed that it would be possible to prepare a report comparable to
the reviews of scientific literature that appear from time to time in various
scientific journals. During the development of the project, according to the
author, it became apparent that the initial plan would have to be modified,
and the decision was made to prepare informative abstracts of the original
articles arranged in chronological order of their appearance.
The considerations that led to the decision are summarized as follows:
1. The articles and reports are largely individual in nature, nonse-
quential, and unprogrammatic.
2. In every case, the form of presentation of the results of experiments,
test procedures, etc., was prescribed by the regulation military
practice.
3. A considerable amount of data and information is contained in the
reports, and it is of such a nature that its appraisal for scientific
merit and usefulness should be made by a wide circle of competent
scientists.
This report consists of 106 abstracts, plus three tabular summaries of
the reported data on the reliability of the test devices, their intercorre-
lations, the data derived from validation studies, an index of the topics
treated in the reports, and an evaluation of the work done and the results
achieved.
96 pp. no figures 96 tables 100 references
Availability: National Technical Information Service (NTIS), 5285 Port
Royal Road, Springfield, VA 22161.
35
OCR for page 36
A Bibliography on Dark Adaptation
Dorothea J. Crook, John ~ Hanson,
Patricia I. McBride, and Joseph W. Wulfeck
1953
Between 1930 and 1950 probably no aspect of vision has deserved
or received more attention than night vision and dark adaptation. In
response to the demands of two wars, biochemical and electrophysiological
research have received increased support. The requirement that specified
levels of dark adaptation be maintained, the need for finding an alternative
for total darkness in becoming dark adapted, and the hope of speeding
up dark adaptation have resulted in widespread efforts to identify and
establish the ranges of the variables affecting the instantaneous threshold
and the subsequent course of dark adaptation. In addition, numerous night
vision testers have been developed and masses of normative, validity, and
reliability data have been accumulated.
An Annotated Bibhog~aphy on Visual Performance at Low Pholopic Illu-
mu~aiion Levels has been prepared by Rock The research on development,
validity, and reliability of night vision testers has been summarized in a
comprehensive report by Berry. Reviews by Adams in 1929 and by Lythgoe
in 1940 have emphasized the mechanisms and theory of dark adaptation,
but the literature dealing specifically with the experimental data on dark
adaptation, especially as related to its associated variables and their ranges,
has grown more and more extensive and scattered.
This bibliography brings together a number of such references in an
effort to make these experimental data more easier accessible. While it
includes items relating dark adaptation to many variables, its basic concern
is with the effects of pre-exposure variables. The heaviest emphasis is on
the effects of the duration and the intensity of the preceding light, and the
relation between them. There is also a fair sampling of references on the
effect of wavelength of the preceding light. In addition to material on the
effects of intensity, duration, and wavelength, literature from other areas is
included.
27 pp. no figures no tables 417 entries
Availabiluy: National Technical Information Service (NTIS), 5285 Port
Royal Road, Springfield, VA 22161.
36
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Report of the Working Group on Illumination
and Dark Adaptation
William S. Ve~planck
1953
This group was appointed for the purpose of preparing a critical review
of the literature on dark adaptation as a function of antecedent conditions
of illumination, with emphasis on wavelength. This summary notes that the
project involved the preparation of a bibliography, the review of papers
cited in this bibliography, with the preparation of evaluative abstracts of
each, and finally, the publication of a paper summarizing the status of
knowledge on this and closely associated topics. For a number of reasons
it proved impossible for the working group to carry this task through to
completion. This report describes the work achieved and the arrangements
made for its completion.
3 pp. no figures no tables 9 references
Availability: Committee on Vision, 2101 Constitution Ave.
ington, D.C. 20418.
1
37
~ N.W., Wash-
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Effect of Flashes of Light on Night Visual Acuity
Part I
.
Glenn ~ Fry and Mathew Alpern
1953
The purpose of this study is to find out the ability of the eye to see
a dark object against a sky background at night after the eye has been
exposed to a flash of light or a series of flashes. A peripheral test object
and a fixation point have been used for measuring the ability of the eye
to see. This investigation has succeeded in demonstrating the operation of
three basic principles: (1) The adaptation of any given part of the retina
can be regarded as being independent of adaptation processes in other
parts of the retina. (2) Reciprocity between time and intensity can be
assumed to hold at least over a three-second interval. (3) The effect of a
flash displaced from the part of the retina used in viewing an object can
be accounted for in terms of stray light. The amount of stray light falling
at any given part of the retina can be computed from the Stiles-Holladay
equation.
The exposure of the eye to a flash patch not only impairs the capacity of
the photoreceptors to respond to subsequent stimulation but also produces
a positive afterimage. A complete understanding of the effect of a flash
of light cannot be claimed until the role played by this positive afterimage
is taken into account. When the flash patch is exactly the same size
and shape as the test patch, it might be questioned whether small eye
movements, which cause a fresh portion of the retina to receive a portion
of the image of the test patch, might affect the results. Consequently,
exploratory experiments have been undertaken with much larger flash
patches to investigate the role played by this factor.
In all of this work, the site of the beam entering the eye has been
restricted by artificial pupils, which are smaller than the natural pupil, so
that variations in the size of the natural pupil have not influenced the
results. There are changes in pupil size that occur as a result of a flash of
light, but it was decided to study these effects in a separate investigation,
which is described in another report (see Effect of Flashes of light on Light
Heal Acute: PA II).
28 pp. 19 figures 1 table 7 references
Availabilz~: National Technical Information Service ~S), 5285 Port
Royal Road, Spnngfield, VA 22161.
38
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Effect of Flashes of Light on Night Visual Acuity:
Part II
Glenn ~ Fry and Merrill J. Allen
1953
The objective of this study is to discover a satisfactory method of pre-
dicting the course of constriction of the pupil of a dark-adapted eye when
exposed to a flash of any duration or a series of flashes involving a complex
and changing distribution of brightness in the visual field. This problem
is quite complicated for several reasons. It involves the differential distri-
bution of rods and cones over the retina with their independently varying
states of adaptation and speeds of reaction. It involves the distribution
of ganglion cells and their connections through the bipolars with the rods
and cones. It involves the mechanism in the midbrain for summating the
impulses received simultaneously from various areas of the retina and also
the mechanism for summating impulses spread out in time; it also involves
the response of the sphincter muscle of the iris to the pattern of impulses
relayed to it by the ciliary ganglion from the Edinger-Westphal nucleus.
The role played by stray light has to be taken into consideration; this is
particularly important in the case of a bright patch subtending a small solid
angle and having a dark background. The small number of photoreceptors
stimulated director by the bright patch might well have a negligible effect on
pupil constriction in comparison with the effect produced by the thousands
of photoreceptors that are stimulated only by the stray light in the eye.
In the experiments described in this report, the beams of light entering
the eye are restricted by artificial pupils normal to the axes of the beams.
17 pp. 18 figures no tables 12 references
Availability: Committee on Vision, 2101 Constitution Ave., N.W., Wash-
ington, D.C. 20418.
39
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The Effect of Pre-Exposure on Dark Adaptation:
An Annotated Bibliography
Patricia I. McBride, Dorothea E. Johannsen, and Joseph W. Wulfeck
1955
The relation between pre-exposure and the course of the subsequent
dark adaptation is of special interest from both the theoretical and practical
points of view. This bibliography summarizes research concerned with the
effects of different pre-exposure variables on subsequent dark adaptation.
Since this bibliography is concerned only with the effects of pre-
exposure variables, only those parts of experiments that include the effects
of pre-exposure are described. In a few instances, holding to this policy
resulted in the elimination of large portions of a study; most of the experi-
ments are fully described, however. Coverage of references is intended to
be comprehensive through spring 1954.
An attempt was made to summarize the important results. The manner
in which the data were originally presented (tabular or graphic) is indicated.
If an experiment consisted of several parts, the results from each part are
identified by numbers.
60 pp. no figures no tables 69 references
Availability: National Technical Information Service (NTIS), 5285 Port
Royal Road, Springfield, VA 22161.
40
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Flash Blindness Symposium:
Proceedings of the U.S. Army Natick Laboratories
John M. Davies and David T. Randolph, Editors
1967
The purpose of this symposium, and the report based on it, was to
arrive at an understanding of the state of knowledge in flash blindness
technology, with the underlying aim of determining how this information
could or should be applied to military problems.
Considering our use of light as a weapon, the eye is among the most
valuable targets. The cornea and lens of the eye may be damaged in various
ways by exposure to intense light, but the most critical visual component
is the retina. Injury to the retina may take the form of retinal lesions; the
effect of the injury then will depend partly on the location. Small lesions
may cause very little decrement; if on the fovea, the loss of vision may be
nearly complete. Even if not on the fovea, a severe chonoretinal lesion may
allow blood to flow into the vitreous body; this type of blindness may be
temporary. This symposium concentrated upon the temporary degradation
of vision caused by bleaching of the visual pigments, such as rhodopsin and
cyanolate, chlorolate and erythorolabe, and the effects that may follow that
bleaching.
In recent flash blindness studies, rather short-duration blinding flashes
have been used, sometimes as short as the microsecond range, but now
even shorter pulses are available. Lasers with pulse durations as short
as perhaps 30 nanoseconds have been used to produce retinal lesions.
Apparently, these devices have not been used to produce flash blindness.
Another phase of the symposium needs specific mention. A part of
it was concerned with eye protection; the discussion was based primarily
upon classified information and is not included in the written summary.
265 pp. 95 figures 17 tables 49 references
Availability: AD 697793, National Technical Information Service (NTIS),
5285 Port Royal Road, Springfield, VA 22161.
41
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Night Vision: Current Research and Future Directions
Symposium Proceedings
1987
Night vision encompasses many different visual functions under a
variety of ambient lighting conditions. Since night operations are a crucial
part of around-the-clock combat readiness, the U.S. Air Force has been
interested in evaluating visual performance at night. A working group
addressed the topic of night vision with four specific objectives in mind: (1)
a definition of the relevant parameters of night vision; (23 an update of the
literature pertaining to night vision, especially new findings, test procedures,
and concepts since 1950; (3) the development of guidelines for establishing
a comprehensive night vision laboratory; and (4) recommendations for the
development of night vision screening tests.
The first two objectives were addressed by convening a symposium at
Brooks Air Force Base in 1985. The proceedings of the symposium form
the basis of this report. The findings and recommendations presented here
are based on working group discussions following that meeting. Reference
is made throughout this section to the papers in this volume that have some
relevance to the recommendations under discussion.
The recommendations address five broad topics: (1) the specification
of ambient illuminance levels; (2) task analysis and characterization of the
work environment; (3) research areas of potential utility to the development
of night vision tests; (4) the development of night vision screening tests;
and (5) recommended equipment for a night vision laboratory.
This report contains 19 papers in addition to the summary report.
335 pp. 80 figures 13 tables 511 references
.
Availability: Publication on Demand, National Academy Press, 2101 Con-
stitution Ave., N.W., Washington, D.C. 20418.
42
Representative terms from entire chapter:
dark adaptation
