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CLINICAL APPLICATIONS
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Manual of Instructions for Testing Heterophoria and
Prism Divergence at Near
1947
This report is an instruction manual for testing heterophoria, a condi-
tion in which the eyes have a constant tendency to deviate but are prevented
from so doing by fusion. When a person looks at an object, an image of
that object Is formed separately in both the right and the left eye. These
separate images are sent to the brain, where they are associated and in-
terpreted as a single unage; this process is known as fusion. Fusion is
responsible for the two eyes working together in harmony; when anything
prevents this, fusion is disrupted and one eye deviates.
For the purpose of heterophona measurement, fusion can be disrupted
by placing a Maddox rod in front of one eye. The image of a spot of light,
when viewed through a Maddox rod, is converted into a line of light. When
the two eyes see unlike images of the same object (one eye sees a spot of
light while the other eye, the one behind the Maddox rod, sees a line of
light), this disrupts fusion and tends to prevent the two eyes from working
together. Thus, when heterophoria is present, the eye behind the Maddox
rod will deviate while the other eye continues to look at or fixate the spot
of light.
The measurement of heterophoria is one of the more difficult problems
that the experienced examiner can meet, because many factors can influence
the test and only a few of these are actually known. Unless the test is
performed in exactly the same way at every testing station, an examinee
may pass the test at one station on one day and fail it on the next day at
another station. A uniformly standardized testing technique must be used
at every station. This manual describes the testing technique to be followed
at all testing stations.
Descriptions of apparatus and procedures are given for testing het-
erophoria and prism divergence with the binocular photometer, with the
portable monocular photometer, and with trial frame and loose prisms.
7 pp. 2 figures no tables no references
Availability: Committee on Vision, 2101 Constitution Ave., N.W., ~sh-
ington, D.C. 20418.
17
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Manual of Instructions
for Clinical Testing of Visual Acuity
1947 (revised 1951)
Visual defects are one of the major causes for physical disqualification
from the Armed Services of the United States. Methods of testing vision
have varied greats among the services and from place to place in each
service; as a consequence, visual test results are not comparable. A can-
didate presenting himself or herself for examination at one center might
be qualified for visual acuity, while at another center he or she would be
disqualified. The purpose of the manual is to descn~e the conditions and
facilities necessary and the procedure to be followed in order to correct
this situation.
The procedures outlined in the manual should be followed by every
person who administers visual tests. It is the duty of the Medical Officer-
in-Charge to supervise and inspect the proper administration of procedures
outlined in this manual.
The manual describes procedures to be followed in testing visual acuity
with wall charts. It is understood that the use of optical instruments may
become sufficiently general at some future date to warrant a revision of the
manual Exact specifications of the test chart, the test room reflectances and
illumination, and occluders are given The procedures for administering
the test are described in detail, including phrases to be used in instructing
the examinee. Scoring procedures are described in full.
19 pp. 11 figures no tables no references
Availability: Committee on Vision, 2101 Constitution Ave., N.W.,
Washington, D.C. 20418.
18
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Report on International Nomenclature
for Designating Visual Acuity
Kenneth N. Ogle
1953
The task of the subcommittee that produced this report was to obtain
a majority point of view regarding a proposal to standardize (1) a partic-
ular mode of designating visual acuity and (2) a particular graduation of
steps in letter size for the visual acuity charts. These two problems are
interdependent and involve a number of fundamental problems.
Many ophthalmologists have insisted that the visual acuity test charts
are primarily for clinical use (1) to determine the effect of certain ocular
diseases on visual acuity and (2) especially to assist in the determination of
the refractive correction for patients. Visual acuity itself is not important
until the final refractive correction is approached in the refraction examina-
tion. The exact manner in which the letters of successive lines of the chart
decrease in size would for this purpose be relatively less important. The
majority of the members of this committee, however, felt that the design of
test charts be such that reasonably accurate determinations of visual acuity
itself could be made.
A uniform decimal scale or fractional designation of visual acuity
requires some type of a uniform graduation in the sizes of the letters
of successive lines of the test chart. There seems to be almost universal
agreement that this graduation should approach that of a geometrical
progression, that is, a graduation in which the size of the letters of one
line bears a constant ratio to the size of the letters in the preceding (or
succeeding) line of the chart. Such a method of preparing a visual acuity
chart gives sizes of test letters of successive lines on the chart, which
increase in a geometric progression. Instead of making all the letters on a
given line of the chart the same size, it may be desirable to design the test
chart so that successive letters increase in size.
The subcommittee made a number of recommendations on the basis
of the discussion and of the considerations presented in the report.
15 pp. 3 figures 1 table 23 references
Availability: Committee on Vision, 2101 Constitution Ave., N.W., ~sh-
ington, D.C. 20418.
19
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Manual of Instructions: Armed Forces Vision Tester
1951 (revised 1952)
This report is a manual of instructions for the Armed Forces Vision
Aster. The Vision Tester is an instrument that may be used to test certain
visual functions of near and far viewing distances. One person is tested
at a time with one instrument. The examinee observes a series of test
slides, some of which test distance vision, others near vision. The examiner
asks standard questions while the emminee is observing each slide and
determines the instrument score from the answers to these questions. The
visual functions examined in the standard form of the tester are vertical and
lateral phoria at distance and near, right and left eye acuity at distance and
near, and depth perception at distance. A special test of distance acuity is
available for testing illiterate examinees. It is also possible to test binocular
acuity at distance and near and prism divergence at near. These special
tests are described in the report
24 pp. 2 figures no tables no references
Availability: Committee on Vision, 2101 Constitution Ave., N.W., Wash-
ington, D.C. 20418.
20
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First Interprofessional Standard for
Visual Field Testing
1975
This report contains a review of basic data and concepts for mea-
surement of visual held and makes the following recommendations: (1)
photometric standards for visual field test equipment should be expressed
in luminance units; and that the illuminant and its desired operating charac-
teristics be specified by the manufacturer for each visual field testing device;
(2) in the specification of chromatic stimuli, the wavelength composition of
the stimulus reaching the eye and the C.I.E. (Commission International de
l'Eclairage) chromacity coordinates should be given; (3) background field
luminance, test target parameters [target luminance, size (area), configura-
tion, and exposure duration or rate of translation], viewing distance, and
location of a target in the visual field should be specificable; and (4) office,
field, and screening instrument design should incorporate test parameters
that produce relatively stable response states.
35 pp. 14 figures 3 tables 74 references
Availability: AD 637389, National Technical Information Service ~S),
5285 Port Royal Road, Springfield, VA 22161.
21
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Recommended Standard Procedures for the Clinical
Measurement and Specification of Visual Acuity
1980
The primary objective of this report is to formulate test conditions,
procedures, and criteria that can serve the clinical need associated with
routine ophthalmological and optometric measurement of visual acuity.
The aim is to enable different examiners to obtain the same test results.
The major emphasis is on the standardization of so-called distance
acuity for distances approximating optical infinity. Recommendations are
also made for tests at a suggested near distance of 40 cm (16 inches). The
proposed near tests include (a) measures of acuity with capital letters under
conditions comparable to those used to measure distance acuity and (b)
tests of ability to read continuous text.
45 pp. 21 figures 4 tables 28 references
Availability: Advances in Ophthalmology VoL 41, pp. 103-148, 1980.
22
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Clinical Applications of Visual Psychophysics
Luis M. Proenza, Jay M. Enoch, and Arthur Jampolsky, Editors
1981
The Committee on Vision held a symposium in October 1978 on
applications of psychophysics to clinical problems, in conjunction with the
Second Study Group on Human Vision. The revised and edited proceedings
of this symposium constitute this volume.
Three problem areas were selected for consideration: the utilization
of recently developed contrast sensitivity, the assessment and development
of vision in infants, and localization of anomalies in the visual pathway.
A concluding chapter summarizes the current very active state of the
boundary between basic and clinical visual science.
304 pp. 235 figures 4 tables 312 references
Availability: New York: Cambridge University Press, 1981.
23
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Nutrition, Pharmacology, and Vision:
Proceedings of a Symposium
John E. Dowling, Luis M. Proenza, and Constance W. Atwell, Editors
1982
In November 1981 the Committee on Vision held a symposium on nu-
trition, pharmacology, and vision. The revised and edited papers presented
at this symposium constitute this report
Nutritional research has identified some 45 substances as essential to
our diet (National Academy of Sciences, Science and Technology, a Five-
Year Outlook, W.H. Freeman & Company, 1981~; however the full range of
cellular and tissue functions in which these essential nutritional substances
participate is not known, and it is likely that additional research will identifier
yet other substances as also essential nutrients. Knowledge concerning the
role of some of these essential substances has increased enormously within
the last decade, particularly with regard to neuronal and visual functions.
It is along this new frontier of adding functional pharmacologic insight to
basic structural knowledge that this symposium was directed.
The following papers were presented at the symposium: "Some As-
pects of Vitamin A Malnutrition," J.~ Olson; "Nutrition and Retinal
Degeneration," E.L. Berson; "Selective Loss of 11-CIS Vitamin A in an
Eye With Hereditary Chorioretinal Degeneration Similar to Sector Retinitis
Pigmentosa," C.D.B. Bridges and R.~N Alverez; "Is Taurine an Essen-
tial Amono Acid?" N. Lake; "The Rules of Vitamin E and Unsaturated
Fatly Acids in the Visual Process," W.G. Robison, Jr., et al.; "Choline
Metabolism and the Maintenance of Photoreceptor Cell Structure," R.H.
Masland; "Nutritional Amblyopia," D.L. Knox et al.; "Changes in Retinal
Morphology and Vitamin A Metabolism as a Consequence of Decreased
Zinc Availability," NE. Leure-Dupree and C.D.B. Bridges; "Nutritional
Factors and Dark Adaptation," R.M. Russell; "Neurotransmitter Systems
in the Retina," B. Ehinger; "Function of Neurotransmitters in the Retina,"
N.W. Daw et al.; "The Effects of 13rrosine and Other Nutrients on Neu-
rotransmitter Synthesis in the Brain and Retina," C.J. Gibson et al.; "The
Ib~c Effects of Glutamate and Related Compounds in the Retina and the
Brain," ].W. Olney; and "Pharmacologic Control of Cortical Plasticity,"
J.D. Pettigrew.
144 pp. 39 figures 4 tables 397 references
Availability: The Retina VoL 2, No. 4, pp. 231-375, 1982.
24
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Myopia: Prevalence and Progression
1989
In this report the findings of research published since the early 1800s on
the progression and prevalence of myopia (nearsightedness) are analyzed.
Myopia is the visual condition in which only nearby objects appear in
focus, much like a camera permanently focused at a close distance. In a
"normal" or emmetropic eye, distant objects are naturally in focus, like a
camera focused at infinity. Prevalence estimates from the 1972 National
Health and Nutrition Examination Survey of persons in the United States
between the ages of 12 and 54 years indicate that 25 percent were myopic.
Individual differences are also known to occur in the progression of
myopia. Ophthalmic clinicians widely acknowledge that, once a youngster
becomes myopic, he or she will most likely become more myopic, and this
increase in myopia will stop or slow down sometime in the teenage years
or later. There is, however, a great deal of individual variability in the age
at which progression ceases.
An extensive literature review was conducted. Over 500 articles were
identified, the majority of which had been published in the last 40 years in
English-language journals. A significant number of articles in nineteenth-
century periodicals were also identified. In addition to the literature search,
a limited number of published research findings in languages other than
English were identified.
113 pp. 11 figures 24 tables 266 references
Availability: Distribution Service, National Academy Press, 2101 Consti-
tution Ave., N.W., Washington, D.C. 20418.
25
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Considerations in Contact Lens Use Under Adverse
Conditions: Proceedings of a Symposiums
Pamela Ebert Flattau, Editor
1990
Contact lenses are an alternative method to spectacles for correcting
refractive error. Soft lenses are more comfortable and adaptation is so rapid
that intermittent wear is practical. Disadvantages are fragility, cost, and
inability to correct more than minimal astigmatism without modifications.
Contact lenses are often fitted for cosmetic purposes. Contact lenses also
offer an important alternative, however, to the restrictions presented by
spectacles for engaging in certain activities - such as athletics or working
in steamy or rainy atmospheres. Furthermore, in certain occupations,
contact lenses made it possible to use equipment that would otherwise
be incompatible with spectacle frames (headgear in firefighting equipment
is just one example). Concerns persist, about the effects of such adverse
conditions as: low humidity, low oxygen, environmental irritants (gas,
smoke, dust), and tissue inflammation on contact lens wear.
A working group was established by the Committee on Vision familiar
with the scientific, clinical, and technological aspects of contact lens use,
with special emphasis on their use under adverse conditions. This report
is the proceedings of a symposium organized by the working group held
in San Antonio, Texas, on November 3 and 4, 1988, to describe current
concerns regarding lenses to the military community (see Contact Lens Use
Under Adverse Conditions: Applications in Solitary Aviation).
Approve: 176 pp. 48 figures 11 tables 257 references
Availability: National Academy Press, 2101 Constitution Ave., N.W. Wash-
ington, D.C. 20418.
26
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Contact Lens Use Under Adverse Conditions:
Applications in Military Aviation
.
1990
In response to a formal request from the ltise~vice Aeromedical
Research Panel (TARP), the Committee on Vision formed a working group
to summarize current scientific, clinical, and technological issues in the use
of contact lenses and to review the operational requirements of military
personnel to the use of contact lenses under adverse conditions. These
conditions are understood to challenge the integrity of the cornea and
include the following effects: (1) hypomc effects (oxygen deprivation), (2)
mechanical effects (cornea! shape changes), (3) biochemicalIbiophysical
effects (dry eye syndrome, corneal swelling, epithelial insult, etc.), and (3)
infection and inflammation (bacterial, viral, fungal, allergies, etc.~.
This report identifies the critical factors to be taken into account by
the military services in adopting a formal position on the use of contact
lenses by U.S. military personnel (see Considerations us Contact Liens Use
Under Adverse Conditions: Proceeding' of a Symposium).
44 pp. no figures no tables 40 references
Availabdity: Publication on Demand, National Academy Press, 2101 Con-
stitution Ave., N.W., Washington, D.C. 20418.
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Representative terms from entire chapter:
contact lenses
