Dark Adaptation Test Research Articles

Effect of hyperthermia on peripheral dark adaptation rates

Supersonic or hypersonic aircraft flight can produce hyperthermia in crew members. Dark adaptation is a physiologic response possibily influenced by such stress. Biochemical regeneration rate of rhodopsin might be altered if retinal blood or tissue temperatures are raised by this hyperthermia. Peripheral dark adaptation curves were obtained on five subjects at comfort (21.0 C) and 65.6 C temperatures alternately, using a modified Hecht-Schlaer adaptometer. In 24 heat experiments, subjects were exposed to 65.6 C ambient air temperature for 55 min after which the heat was shut off. Chamber temperature declined but the subjects remained in a relatively constant hyperthermic condition during the subsequent 35-min dark adaptation test. The criterion used here for hyperthermia is the elevation and maintenance of the rectal temperature at least 0.56 C above corresponding control temperature. Curves obtained under hyperthermic conditions (with the exception of the initial and terminal values) differ, with statistical significance, from controls, indicating a facilitation of dark adaptation under the imposed thermal stress conditions.

Variability of Dark Adaptation

Dark-adaptation curves were obtained from three observers: one was tested 15 times, the others 24 times each. Half of the tests were taken immediately upon entering the darkroom, the other half after 30 minutes rest in total darkness. The variability of threshold measurements is approximately twice as large in the former as in the latter condition. It appears that exposure to light prior to the standard procedure of testing exerts an influence upon subsequent threshold measurements, unless the visual receptor system is allowed to reach a state of equilibrium before the standard pre-exposure is given. This assumption is supported by experiments in which two observers spent half an hour reading under bright outdoor skylight. When the eyes are not shielded from high luminances, or when luminance is only slightly reduced, the delayed dark adaptation curves reach lower levels than when the tests are made immediately. However, when the eyes are shielded by dense goggles dark-adaptation curves obtained in immediate and delayed tests are indistinguishable. It seems probable, therefore, that variability in dark adaptation is at least in part a function of residual effects of exposure to light antecedent to routine pre-exposure and threshold measurements in dark-adaptation tests.

Automatic intensity control in testing dark adaptation.

In clinical practice quantitative dark adaptation tests are frequently avoided for several reasons. For example, the examination requires more time than the physician is usually able to devote to it, even if he is thoroughly familiar with the instrument and the technique. Since the test is not used routinely, it is difficult either to establish a standard procedure or to have an experienced technician available when needed. Furthermore, the test is of such a nature that much of its value is lost if standard procedures are not followed. These difficulties have been partly met by developing an apparatus which provides simplification and standardization of the procedures. These improvements were added to the standard Goldmann-Weekers adaptometer, which is the most commonly used modern adaptometer for clinical studies. Besides other advantages, the apparatus includes an arrangement for uniform preadaptation and a self-recording system. The determination of the brightness threshold is made in

Treatment of Acne Vulgaris and Senile Keratoses with Vitamin A: Results of a Clinical Experiment

Recent advances in our knowledge of the relationship between vitamin A and cutaneous disorders are numerous but not spectacular. While a number of new dermatoses have been added to the list of those which appear to respond at least occasionally to the administration of vitamin A, such as leukoplakia vulvae (1), porokeratosis Mibelli (2), keratosis blennorrhagica (3), acrokeratosis verruciformis (4), pili torti (5), and hyperkatosis follicularis et parafollicularis in cutem penetrans (6), studies of the working mechanism of the substance have not been particularly successful. It was determined by chemical assay (7) that there is little evidence to show that dermatologic conditions influence or are influenced by the amount of vitamin A in the blood plasma. On the other hand, determination of the level of the vitamin in the blood serum of 8 normal persons and 11 patients with dermatologic disease following the administration of massive doses showed abnormally flat curves in patients with keratosis foilicularis, congenital dyskeratosis and infantile eczema (8). The response to the dark-adaptation test of patients with various dermatoses was reported not to differ significantly from that of persons with normal skins (9). It is likely that the advent of the aqueous preparations of the vitamin will facilitate bio-chemical studies; early reports (10) indicate their greater ability to raise the vitamin A level of the blood serum. We have been concerned for several years with the effect of the vitamin on the pathologic changes of the pilo-sebaceous follicle in acne vulgaris (11), a subject on which other investigators have recently reported their observations (12, 13). Since we were unable to arrive at definite conclusions about the efficacy of the therapy we decided to conduct a controlled clinical experiment which might yield more accurate data. After the experiment was well under way we read with interest the report of an exceptionally well-controlled and conducted experiment on the effect of vitamin A therapy on keratoses (14). The importance of a practical method for the control of precancerous lesions of the keratosis type was the reason for the second study.

Specifications for Dark-adaptation Tests

Specifications for Dark-adaptation Tests

The occurrence of avitaminosis A in diseases of the Liver

The dark adaptation test for Vitamin A deficiency was utilized in 36 patients with various forms of liver disease. The results show that this procedure is of value in the estimation of hepatic parenchymal damage with the inference that such a process is associated with a change in Vitamin A metabolism. Jaundice of itself showed no particular effect on dark adaptation. The prothrombin level did not parallel the dark adaptation test in 50% of the cases investigated, although the liver function tests and dark adaptation were indicative of liver damage.

Dark-adaptation Tests and Vitamin A Deficiency

Dark-adaptation Tests and Vitamin A Deficiency

Vitamin A in Pregnancy : II. Comparison of Dark Adaptation and Serum Tests

Vitamin A in Pregnancy : II. Comparison of Dark Adaptation and Serum Tests

A comparison of two methods of measuring dark adaptation

<h2>Summary</h2> The results of dark adaptation tests obtained with the biophotometer and with the Hecht-Schlaer adaptometer on the same subject have been compared. It was found that the biophotometer does not use a bright enough bleach light to bleach the cones, so that cone adaptation is absent from the biophotometer curve. When the intensity of the bleach light is increased, however, the cone adaptation may be measured with the biophotometer. Within the limits of error, the rod adaptation as measured with the biophotometer and the Hecht-Schlaer adaptometer is identical. The first reading obtained after the bleach period with the biophotometer is felt to represent the final cone threshold as determined with the Hecht-Schlaer instrument. Consequently, it is, felt that the continued use of the biophotometerin the study of vitamin A deficiency is valid, giving a true picture of dark adaptation. It is suggested that measurements of dark adaptation be continued for fifteen or twenty minutes following the bleach period in the biophotometer test.

MEASUREMENT OF VITAMIN A STATUS OF YOUNG ADULTS BY THE DARK ADAPTATION TECHNIC

With the recognition that cases of mild, subclinical vitamin deficiency are much more common than cases of severe deficiency, the need for adequate diagnostic methods for early avitaminotic states is urgently felt by clinicians. Only by such methods can the clinician determine the borderline states of malnutrition that not only contribute to his patients' ill health but prevent the best response to therapeutic measures. As a criterion of deficiency of vitamin A, the night blindness or dark adaptation test is valuable, especially since the work of Wald, 1 Wald and Clark, 2 Hecht and his co-workers 3 and others has demonstrated the physiologic role of vitamin A in the generation of the visual purple. Impairment of the visual cycle occurs as one of the first signs of an inadequate supply of vitamin A. Jeghers 4 has reviewed the literature on this test, and Hecht 5 has reviewed the literature on this test, and Hecht 5 has

Vitamin A status of children as determined by dark adaptation

Summary The purpose of this investigation was to determine the frequency with which vitamin A deficiency is encountered in children. In view of the fact that vitamin A deficiency brings about an elevation in the final rod threshold, i.e., the minimum intensity of light observed by the subject after complete dark adaptation, we made use of the final rod threshold level as a criterion of vitamin A deficiency. Accordingly, the final rod threshold was determined in 144 children ranging in age from 6 to 12 years. Sixteen of these children were private patients, whereas the remainder were observed either in the wards or in the Outpatient Department at Bellevue Hospital. Forty-two children had rheumatic fever, fourteen had pneumonia, six had active tuberculosis, and the remainder were suffering from one of the following conditions: upper respiratory infection, lung abscess, bronchiectasis, Hodgkin's disease, diabetes, renal calculus, malformation of the ureter, malnutrition, sickle cell anemia, dysentery, hemophilia, vaginitis, and asthma. Dark adaptation tests revealed normal threshold values in all but one instance. The sole exception was in a child who, because of abdominal pain, had been placed on a rigorous diet which was low in vitamin A. Administration of 120,000 units of vitamin A in the form of percomorph-liver oil brought about a fall of the threshold to a normal value in thirty-five minutes. The effect of this enormous dose lasted twenty days, at the end of which time the threshold again reached an abnormally high level. The provitamin, carotene (120,000 units) was then given, and a prompt response was again noted, the threshold returning to normal in thirty-two minutes. This child was then placed on a regular diet, and repeated tests over a period of several months have revealed normal values. The results of this investigation indicate that vitamin A deficiency, as judged by dark adaptation, is an uncommon disorder in children in New York City.

Vitamin A requirements in infancy as determinedby dark adaptation

Summary The minimum light threshold after complete dark adaptation was determined in 53 infants ranging in age from 1½ to 13 months. These infants were divided into four groups: Group 1 consisted of 26 infants receiving the average infant's diet; Group 2 consisted of 9 infants receiving a diet supplemented by large quantities of vitamin A (17,000 units) in the form of halibut-liver oil; Group 3 consisted of 4 infants, receiving a diet containing approximately one-fourth the vitamin A content of the average diet; and Group 4 consisted of 14 infants receiving about one-twelfth the vitamin A content of the average diet. These diets were given for periods varying from 3 to 10 months. The results of the dark adaptation tests were within normal limits in all four groups of infants. Thus, infants receiving only 135 to 200 vitamin A units daily had as low a threshold for vision in the dark as infants receiving an average diet supplemented by 17,000 vitamin A units. It should also be added that the infants in the low vitamin A group gained weight just as well as, and were no more susceptible to infections than, those in the high vitamin A group. These observations indicate that 135 to 200 units of vitamin A (approximately 25 units per kilogram of body weight) covered the minimum vitamin A requirements in these infants. Since the average diet contains approximately 12 times as many units of vitamin A as were contained in our low vitamin A diet, it is apparent that there is a large margin of safety in the infant's diet with respect to its vitamin A content. It would, therefore, seem unnecessary to supplement the average diet of infants with special preparations which contain vitamin A. Three infants, two of whom had eczema, received as a substitutefor milk a proprietary preparation containing soy bean, starch, and olive oil. This product is almost devoid of vitamin A. In 3 to 4 weeks these infants manifested poor dark adaptation. The addition of 120 units of vitamin A in the form of cod-liver oil resulted in normal dark adaptation in two of these infants. Computed on the basis of kilogram body weight this dosage (plus the vitamin A content of the diet) was equivalent to 18 units of vitamin A for one infant and 20 units of vitamin A for the other infant. When a single large dose of vitamin A, 30,000 to 50,000 units, was given to two infants who had developed high threshold values on this diet, a prompt response occurred; dark adaptation returned to normal in 40 minutes in one infant and in 65 minutes in the other infant. During the period that the three infants on the soy bean diet hadpoor dark adaptation, they gained well in height and in weight and were no more susceptible to infections than infants receiving large quantities of vitamin A. In view of the fact that these infants appeared normal in every way, we must conclude that they had a latent or subclinical form of vitamin A deficiency which became evident only as a result of the dark adaptation tests.

The Dark Adaptation Test for Vitamin A Deficiency

The Dark Adaptation Test for Vitamin A Deficiency Carroll E. Palmer CopyRight*Read before the Child Hygiene Section of the American Public Health Association at the Sixty-sixth Annual Meeting in New York, N. Y., October 5, 1937. https://doi.org/10.2105/AJPH.28.3.309 Published Online: August 29, 2011

SIGNS OF VITAMIN A DEFICIENCY IN THE EYE CORRELATED WITH URINARY LITHIASIS

In this study our aim was to determine, if possible, any relationship that may exist between vitamin A deficiency and upper urinary lithiasis in human beings. In order to prove or disprove such relationship, we decided to test for vitamin A deficiency a group of individuals who have or have had renal or ureteral calculi. The method employed was the dark adaptation or light sensitivity test. In the absence of demonstrable disorders of the eye, an increase in the light sensitivity (dysaptation) is an indication of the failure of the regeneration of the visual purple. One of the main causes of this condition is lack of vitamin A. EXPERIMENTAL DATA The substance or nutritional factor known as vitamin A was discovered through experiments made independently and almost simultaneously in 1913 by McCollum and Davis1and by Osborne and Mendel.2Young experimental animals were found to thrive or to

RODS, CONES, AND THE CHEMICAL BASIS OF VISION

ArticlesRODS, CONES, AND THE CHEMICAL BASIS OF VISIONSelig HechtSelig HechtPublished Online:01 Apr 1937https://doi.org/10.1152/physrev.1937.17.2.239MoreSectionsPDF (7 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInEmailWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformationCited ByPhysiological Optics15 July 2004Dark adaptation and the retinoid cycle of visionProgress in Retinal and Eye Research, Vol. 23, No. 3Bleaching desensitization: background and current challengesVision Research, Vol. 43, No. 28Chapter 27 Dark adaptationChapter 29 Light adaptation and contrast in the outer retinaVisibility, luminance and vernier acuityVision Research, Vol. 33, No. 4Elements of photometry, brightness and visibility18 August 2016 | Lighting Research & Technology, Vol. 24, No. 1Rhodopsin and visual adaptation: Analysis of photoreceptor thresholds in the isolated skate retinaVision Research, Vol. 24, No. 4Flicker fusion characteristics of rod photoreceptors in the toadVision Research, Vol. 23, No. 9The compression model: A re-examinationVision Research, Vol. 21, No. 10Evidence for the equivalent-background hypothesis in conesVision Research, Vol. 19, No. 7Scotopic hues of simultaneous contrastVision Research, Vol. 18, No. 11The effects of photopigment depletion on brightness and thresholdVision Research, Vol. 18, No. 3Lateral spread of light adaptation in the rat retinaVision Research, Vol. 17, No. 3Color vision from rod and long-wave cone interactions: Conditions in which rods contribute to multicolored imagesVision Research, Vol. 17, No. 2Absence of rod activity from peripheral visionVision Research, Vol. 16, No. 12Scotopic contrast hues triggered by rod activityVision Research, Vol. 15, No. 10Rhodopsin cooperativity in visual responseVision Research, Vol. 15, No. 1Chromatic rod activity at mesopic intensitiesVision Research, Vol. 13, No. 12Chromatic rod vision—IX. A theoretical surveyVision Research, Vol. 13, No. 2Photoproducts of retinal photopigments and visual adaptationVision Research, Vol. 12, No. 5Flicker adaptation—II. effect on the apparent brightness of intermittent lightsVision Research, Vol. 12, No. 4Effect of dark and light adaptation on the retina and pecten of chickenExperimental Eye Research, Vol. 13, No. 1The suppression-recovery effect and visual adaptation in the catVision Research, Vol. 11, No. 12The independence of the photopic receptor systems underlying visual thresholds in a teleostVision Research, Vol. 11, No. 8Mathematical analysis of rhodopsin kineticsVision Research, Vol. 11, No. 5Temporal and spatial interactions involved in the band movement phenomenonVision Research, Vol. 9, No. 6Scotopic and photopic functions for visual band movementVision Research, Vol. 9, No. 2The flash-evoked afterdischargeBrain Research, Vol. 9, No. 2Transient and steady state electroretinal responsesVision Research, Vol. 8, No. 3Neural limitations of visual excitability VIII: Binocular convergence in cat geniculate and cortexVision Research, Vol. 6, No. 7-8Effects of light- and dark-adaptation processes on the generator potential of the Limulus eyeVision Research, Vol. 2, No. 5-6Rod and cone receptor mechanisms in typical and atypical congenital achromatopsiaVision Research, Vol. 1, No. 1-2Developments in the physiology of color vision since EinthovenAmerican Heart Journal, Vol. 61, No. 3Visual Pigments in Man and Animals and their Relation to SeeingProgress in Biophysics and Biophysical Chemistry, Vol. 9Fifty years of ophthalmology in the United StatesThe American Journal of Surgery, Vol. 51, No. 1THE DARK-ADAPTATION TEST: ITS RELIABILITY AS A TEST FOR VITAMIN-A DEFICIENCYThe Lancet, Vol. 234, No. 6070 More from this issue > Volume 17Issue 2April 1937Pages 239-290 https://doi.org/10.1152/physrev.1937.17.2.239History Published online 1 April 1937 Published in print 1 April 1937 Metrics

DARK ADAPTATION AND VITAMIN A

In 1934 we 1 described a photometric test for detecting moderate degrees of vitamin A deficiency by determining ability to adapt to darkness. The observations that formed the basis of the former report were made with a Birch-Hirschfeld photometer. For reasons discussed subsequently this instrument is not adapted for satisfactory use in the manner employed. Because of the difficulties encountered, a new photometer has been devised especially for the dark adaptation test. It is our purpose in this publication to describe the use of the new photometer and also certain experimental observations that have been made with it. 2 The new photometric technic makes use of the same basic principles as were described in our previous report. Scotopic vision is observed with relation to exposure to a bright light and to a period in darkness. The observations are made by determining the amount of light necessary for the subject to

THE PREVALENCE OF VITAMIN A DEFICIENCY AMONG IOWA CHILDREN

In 1934 we¹described a photometer test for dark adaptation which we believed useful in detecting vitamin A deficiency. Subjects with impaired ability to adapt to the dark were found to attain normal standards of dark adaptation after a period of vitamin A ingestion. The study that was reported seemed to establish the validity of the dark adaptation test as a test of vitamin A deficiency. With the photometer test being used as the criterion, a survey was made among Iowa school children in an endeavor to determine the frequency of vitamin A deficiency. This presentation is for the purpose of recording the results of the survey. The first phase of the study, i. e., the original testing, was conducted in 1934 from February to April inclusive. The total group examined comprised 404 children from 6 to 15 years of age selected at random from rural, village and urban