J. J. Meyer

Petites variations du taux sanguin de vitamine A et leurs incidences sur la perception visuelle

The purpose of this study was to find out a simple perceptual visual test that gives the possibility to detect the visual incidence of slight variations of the vitamin A blood rate. The visual function was tested in 30 young subjects without refraction problems at the same time as blood concentration of vitamin A was measured. Visual tests comprised visual acuity at high and low luminance level, contrast sensitivity, glare sensitivity as well as attenuation characteristics of the eye toward flickering stimuli. Among all these tests, only the flicker test showed some relation with the plasma vitamin A levels, which were situated between 35 and 75 mcg/100 ml.

The Functional Examination of the Human Photopic Visual System with the Aid of Psychophysical Flicker Thresholds and ERG Flicker Responses

This paper deals with the use of flicker fusion thresholds, as plotted by De Lange, and averaged flicker ERG recorded with conventional clinical equipment. Different methods are developed to quantify the morphological changes of the ERG responses and express them in empirical attenuation curves. The objective and subjective results are discussed in point of view of the De Lange model.

Measurements of the visual performance of visitors to the Ideal Home Exhibition using a new prototype

The visual examination of drivers is usually limited to the measurement of photopic visual acuity. This study shows that it would be more appropriate, particularly for night driving, to measure the recovery time after glare, as well as the acuity-luminance relationship in mesopic conditions.

An Automatic Intermittent Light Stimulator to Record Flicker Persceptive Thresholds in Patients with Retinal Disease

Modern life implies more and more the extensive use of vision. Although artificial lighting is extending at a faster rate, although visual displays are more and more invading the workplace, eye doctors do not know much about this particular variable which affects the normal as well as the pathological eye.

Contribution à l'étude de la charge visuelle aux postes de travail avec écran de visualisation*

The ergonomic study of VDUs demonstrates the importance of visual stress in the total work load. By means of a laboratory experiment and authors showed that the distribution of light in the visual field exerts a major influence on the operators visual acuity. For this reason, it is of great interest to measure the visual performance in light conditions as close as possible to real working conditions. The results of this experiment can also be of practical value in formulating guidelines for the design of appropriate work places corresponding to the visual requirements of VDU operators.

Est-il dangereux de fréquenter les discothèques?

ZusammenfassungIn 6 Konzerten wurden Lautschallstärken zwischen 92 und 105 dB(A) mit Spitzen von 120 dB(A) gemessen. Mit Hilfe von Audiogrammen vor und nach den Konzerten konnte eine bedeutende Hochmüdigkeit festgestellt werden. Des weiteren konnte festgestellt werden, dass die Hörempfindlichkeit der Musiker und der häufig anwesenden Zuhörer inbezug auf eine Vergleichsgruppe derselben Alterstufe leicht herabgesetzt ist.SummarySound levels measured during 6 music-exhibitions are situated, for the equivalent level (Leq), between 92 and 105 dB(A), and peaks of 120 dB(A) have been measured. Audiograms recorded before and after the exhibitions show a great auditive fatigue. Musicians and usual spectators present in comparison with nonexposed subjects of the same age a lightly impaired sensibility of hearing.

Plaintes visuelles, déficits fonctionnels et carences vitaminiques

: The comparison between complaints, functional defects and vitamin deficiencies is reported for several professional groups characterized by different work conditions. Results suggest that complaints are an useful indicator of visual load and that retinal sensitivity to the light is especially tried. Longitudinal studies are required to verify whether some functional alterations on the aging process of the eye can be aggravated by a visual overload. Visual complaints, functional defects and vitamin deficiencies as indicators of visual load.

L'électrorétinogramme (ERG) moyenné de rats exposés à deux organomercuriels

ZusammenfassungIn Ratten, die PHB-und CH3HgCl Injektionen bekommen hatten, wurde das mittlere ERG untersucht. Nur in CH3HgCl-Ratten wurde die Potentialhöhe des ERG signifikant verändert. In Zusammenhang bemerkte man, dass das totale Quecksilber in den Augen der CH3HgCl-Ratten viel höhere Werte zeigte als in PHB-Ratten.SummaryAveraged ERGs of rats treated with phenylmercury borate and methylmercury chloride were recorded. Amplitude differences were seen only with the latter treatment. A high Hg tot. level was found in eyes of animals treated with methylmercury.