le travail à l'écran de visualisation work with display units

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ECRANS CATHODIQUES A INFORMATION CODEE EN COULEUR ETPERFORMANCE VISUELLEJohn V Lovasik OD PhD, Hélène Kergoat LScO MSc*, Ecole d'Optométrie, Université deWaterloo, Ontario. Michael L Matthews BA PhD, Département de Psychologie, Universitéde Guelph, Guelph, Ontario. (*Conférencière)Diverses études (ex. Dainoff 1982, Knave et coll. 1985) ont décrit le genre de symptômesreliés à l'utilisation d'écrans cathodiques (ECs), ainsi que leur fréquence. Cependant, peud'études (ex. Ostberg 1980, Gunnarsson et Soderberg 1983, Woo et coll. 1987) ont tentéde quantifier les changements optiques et oculo-moteurs pouvant affecter le systèmevisuel, après un travail prolongé sur ECs. L'objectif de la présente étude était de quantifierles effets possibles d'un travail prolongé sur ECs à information codée en couleur, sur lafonction visuelle. L'influence de symboles monochromatiques (Couleur des symboles etde l'arrière-plan: blanc/noir, rouge/noir, vert/noir, et bleu/noir) et multichromatiques(bleu/rouge, bleu/vert, et rouge/vert), égalisés en brillance à l'aide d'une méthodepsychophysique, et présentés sur ECs a été examinée à trois niveaux, 1) Neural: Lafonction visuo-neurale a été évaluée objectivement à l'aide des potentiels évoquésvisuels (PEVs). 2) Optique: La précision du système de mise au point (accommodation) aété évaluée à l'aide d'un optomètre au laser à haute résolution relié à un programmeinformatique sur ordinateur. 3) Behavioral: L'influence de la couleur des stimuli sur desréponses motrices suite à une tâche visuelle prolongée de recherche/décision a étéévaluée. Vingt sujets visuellement normaux, âgés de 22 à 35 ans, ont été payés pourparticiper à la partie neuraie et optique de notre étude. Les performances neurale etoptique ont été évaluées pour divers stimuli variant en grandeur, en couleur, et selon ledegré de défocalisation optique simulant une mise au point erronée. L'illuminationambiante à la surface de l'écran était de 54 lux. Les mesures de PEVs et d'optomètre aulaser ont démontré que les réponses visuelles neurales et optiques variaientsystématiquement en fonction de la couleur des stimuli (Lovasik et Kergoat, OphthalPhysiol Opt 1988; Kergoat et Lovasik, Can J Optom 1988). Alors que le fait d'augmenter lagrandeur des lettres n'a pas influencé la précision de la mise au point, ni le degré de miseau point entre les différentes combinaisons de couleurs; la performance neurale a étéaméliorée en augmentant la grandeur des cibles de fixation de 14 minutes d'arc à 28minutes d'arc. La troisième phase de notre étude a été conçue de façon à évaluer l'effetd'un travail prolongé sur ECs sur les systèmes neural et accommodatif de l'oeil humain,aussi bien que la performance behaviorale, lors de trois sessions comportant une tâchede recherche/décision d'une durée de 4 heures chacune. Suite aux résultats des étudesneurale et optique, trois combinaisons de couleurs (bleu/noir, rouge/noir, et rouge/vert)ont été examinées. Les cibles ainsi choisies furent celles qui: 1) ont élicité des réponsesneurales et accommodatives inférieures, 2) ont été jugées moins "visibles" par les sujets,et 3) représentaient des éléments chromatiques aux extrémités du spectre visible. Dixsujets ont participé aux sessions de recherche/décision. Bien que des changementsmesurables dans les réponses neurales et accommodatives aient été obtenus, pourchacune des combinaisons de couleurs utilisées, ils étaient minimes, et la différence dansles mesures des PEVs et de l'accommodation entre les combinaisons de couleurs sontrestées à peu près les mêmes au cours de la tâche de recherche/décision de 4 heures(Lovasik, Matthews et Kergoat, Human Factors, sous presse). Seulement de faiblescorrélations ont été obtenues entre les mesures neuro-optiques et la performancebehaviorale. Ces résultats suggèrent que l'utilisation de stimuli de couleur, pour lescombinaisons de couleurs testées, n'ont pas d'effet détrimentaire sur la performancevisuelle.CHROMATIC VIDEO DISPLAY UNITS (VDUs) AND VISUAL PERFORMANCEJohn V Lovasik OD PhD, Hélène Kergoat* LScO MSc, School of Optometry, University ofWaterloo, Waterloo, Ontario. Michael L Matthews BA PhD, Department of Psychology,University of Guelph, Guelph, Ontario. (* Presenter)Various studies (eg. Dainoff 1982, Knave et al. 1985) have described the type andfrequency of visual symptoms related to VDU usage. However, only a few studies (eg.Ostberg 1980, Gunnarsson and Soderberg 1983, Woo et al. 1987) have attempted toquantify optical and oculomotor changes that may occur in the visual system, afterextended work on VDUs. The objective of the present study was to quantify any effects ofprolonged work with chromatic displays on visual function. The influence of brightnessmatchedmonochromatic (white/black, red/black, green/black, and blue/black) andmultichromatic (blue/red, blue/green, and red/green) symbols displayed on VDUs wasexamined at three levels, 1) Neural: Visual neural processing was assessed objectivelyby visually evoked potentials (VEPs). 2) Optical: Focusing accuracy for letter targets wasassessed with a high resolution computer-aided laser speckle optometer. 3) Behavioral:The influence of target chromaticity on visually directed behavior was evaluated in aprotracted search performance task. Twenty visually normal, paid volunteers between theages of 22 and 35 years were used as subjects in the neural and optical phases of ourstudy. Neural and optical performance were evaluated for stimuli varying in size, color,and three degrees of optical defocus simulating focusing errors. Ambient lighting at thescreen plane was 54 lux. VEP and laser optometer measurements showed that bothneural and ocular focusing responses varied systematically across color targets (Lovasikand Kergoat, Ophthal Physiol Opt 1988; Kergoat and Lovasik, Can J Optom 1988). Whileincreasing the letter size neither improved the focusing accuracy nor the differentialfocusing strategy across target color combinations, neural performance could beenhanced by increasing the target size from 14 arcmin to 28 arcmin. The third phase ofour study was designed to investigate the effect of prolonged VDU work on both thevisual neural and focusing system of the human eye as well as the behavioralperformance, in three separate 4 hour search/decision tasks. Based on the results of theneural and optical studies, three foreground/background combinations (blue on black ,red on black, and red on green) were examined. These targets were those that: 1)elicited inferior neural and accommodative responses, 2) were rated poorly by observersfor "visibility", and 3) represented chromatic elements widely spaced in the visiblespectrum. Ten subjects performed the search/decision task. While there were measurablechanges in the neural and focusing responses to each foreground/backgroundcombinations over time, these were minimal, and the differences in VEP andaccommodation measures across color combinations remained about the same over the4 hour search/decision task (Lovasik, Matthews and Kergoat, Human Factors in press).Only weak correlations were found between neuro-optical and search performancemeasurements. These data suggest that the use of chromatic stimuli, in the colorcombinations examined, do not have a detrimental effect on visual performance.KEYWORDS: VDUs, Accommodation, Visual evoked potentials, Search performance.Mots clés: Ecrans cathodiques, Accommodation, Potentiels évoqués visuels, Performancebehaviorale.TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989136TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE IN TERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989133
HEALTH ASPECTS 01" WORK WITH VDU-S.Hans G Bauer 1 , Gunnar Aronsson 2 , Cari Âborg 1 , Margaretaôrelius 2^The Swedish Foundation for occupational Health and Safety forState Employees, S-371 87 Karlskrona, Sweden. 2 NationalInstitute of Occupational Health, S-171 84 Solna, Sweden.The aim of this retrospective and descriptive questionnairestudy was to investigate health effects of VDU-work. Thequestionnaires were distributed to Swedish State Employeesworking with VDU-s (n = 32 47). The sample was not randomlyselected but represents employees all over the country, workingat 83 different working places. The items covered backgroundvariables, psycho-social and VDU-work invironment, medical andpsychic symtoms, and health-related behavior. This paper isfocused on musculo-sceletal pain, visual and skin problemswhile psycho-social aspects are treated in a separateconference paper (Âborg et al) .The main independent variables studied were:- type of work classified as data entry, data acquisition,interactive communication, word processing and programming,CAD, CAM etc and- hours of work classified as less than 1 hour/day, 1-2 h,2-4 h, 4-6 h and more than 6 hours/day.Results Î 70% of the VDU-operators were women and 30% were men.The mean age was 39 years (range 18-65 years) . The most commontype of work was data entry (16%) , data acquisition (15%) andinteractive communication (41%). Data entry work was to 96%performed by women while 68% of programming etc was performedby younger men (mean age 3 5 years) . The data entry groupdiffered significantly from the other groups in the respectthat they worked more than 6 hours/day with VDU-s.Shoulder muscle pain was most common in the data entry group(51%). The prevalence increased in all groups with hours ofwork/day(6 h/day: 50%) .Eye problems occurred in 71% not significantly more in any ofthe subgroups. The prevalance increased in all groups withworking time (6 h/day: 84%) .Skin problems occurred in about 3 0% in all groups and increasedlittle by number of working hours/day with VDU-s.Conclusion: VDU-operators with data entry, data acquisition andinteractive communication types of work and with a working timeof more than 6 hours/day with VDU-s have a high self-reportedprevalence of cervico-brachial pain, visual and skin problems.These groups are dominated by females. They seem to bethe losers from a medical point of view when office work iscomputerized.OCCUPATIONAL STRAIN AMONG' VDT OPERATORSZhang Dian-Y.e, Department of Human Engineering, Instituteof Industrial Health, Anshan Iron and Steel Co.. Anshan,Liaoning, People ' s Republic of ChinaThe aim of the study was to investigate possible occupationalstrain in the VDT workplace. This matched case-controlstudy involved 1094 participants (VDT group 547, nonVDTgroup 547). Both V'DT user and non-VDT user from the sameunit is similar apart from VDT factor.A questionnaire was designed and conducted on the workersof Iron and Steel Co. The questionnaire included such itemsas age, years of service, subjective symptoms relatedto visual, musculoskeletal and general status.The measurement of VDT workplace included illumination,noise, temperature, humidity, 02 and C02 of atmosphere.The measurement of equipment and human body included suchitems as screen, keyboard, chair, table, body stature,eye height, sitting height, eye to seated surface, elbowrest to seated surface and so on. The posture of operatingwastaken and recorded.The clinical examination and physiologic and psychologicmeasurement were carriedThe following results were obtained: 1) Ahigh incidence ofcomplaints of visual function, i.e. eye strain and blurringof distant objects; musculoskeletal strain, i.e. shoulderor neck pain, low back pain, wrist pain; general symptoms,:i.e. fatigue, gastrointestinal disorders were observed forVDT operators. 2) The rates of these subjective symptomsincreased with years of service. 3) Significant correlationswere not found between these complaint rates and enviromentfactors in workplace. 4) The complaint rates of musculoskeletalstrain tended to increase with working hours andconstrained posture. 5) Tlte indexes of heart rate, ventilation,energy cost were generally non-significant. 6) Psych,-ologic measurement which include response time, OFF valueswas not found significant different for compare between VDTgroup and non-VDT group.KEYWORDS: Visual display terminal (VDT), subjective symptommatched case-control study, occupational strain,working condition.KEYWORDS: Cervico-brachial painVisual and skin problemsWork organization (type and hours of work with VDU-s)1ÏV 1989 —DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989134TEV 1989 - - DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL135SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989
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DEUXIÈME CONFÉRENCESCIENTIFIQUE I
Page 9 and 10:
Résumés /AbstractsTEV 1989 — DE
Page 11 and 12:
VDU USE IN SCHOOLSBengt Knave, Depa
Page 13 and 14:
A TWO-YEAR FOLLOW-UP STUDY OF VISUA
Page 15 and 16:
ETUDE ERGONOMIQUE DU POSTE DE COMMA
Page 17 and 18: OPTIMAL CONTRAST RATIOS FOR VDTsHar
Page 19 and 20: VISUAL COMPLAINTS, EYE IMPAIRMENT A
Page 21 and 22: STRESS AND STRAIN ON CAD-WORK - RES
Page 23 and 24: NOUVELLES TECHNOLOGIES, QUALIFICATI
Page 25 and 26: NEW TECHNOLOGY AND WORKERS' HEALTH:
Page 27 and 28: 6TRAIN ANALYSIS AT WORD PROCESSING
Page 29 and 30: LEARNING BY DISCOVERY : PROCEDURAL
Page 31 and 32: Action facilitation approach to hum
Page 33 and 34: MUSCULOSKELETAL PROBLEMS IN RELATIO
Page 35 and 36: ARE THERE VISUAL INTERACTIONS BETWE
Page 37 and 38: 53AN EVALUATION OF VDT OPERATIONS T
Page 39 and 40: 1-2 - 59FROM TEXT COHERENCE TO INTE
Page 41 and 42: PS 2THE EFFECT OF GRAPHIC COMPLEXIT
Page 43 and 44: PS 2 66EYE-CATCHER: A LOW-COST EYE-
Page 45 and 46: Il 70VDT WORK RELATED FACTORS AND P
Page 47 and 48: THE USE OF VISUAL DISPLAY UNITSIN D
Page 49 and 50: BtUlllBlPanel on the consequences o
Page 51 and 52: MEASURING METHOD OF SPECULAR REFLEC
Page 53 and 54: :3 89VDT LEGISLATION AND REGULATION
Page 55 and 56: C0PIN6 WITH COMPUTER STRESSSten-Olo
Page 57 and 58: REPERES POUR UNE DEMARCHE ET UNE ME
Page 59 and 60: H.î 98H3 99COMPLAINTS OF DISCOMFOR
Page 61 and 62: AN OUTBREAK OF FACIAL SKIN RASH IN
Page 63 and 64: THE EFFECTS OF THE ORGANIZATION OF
Page 65 and 66: PSYCHOSOCIAL ASPECTS OF USING CAD-S
Page 67: ACCOMMODATION CONTROL AND COLORED I
Page 71 and 72: SKIN COMPLAINTS AND VDU WORK; AN EP
Page 73 and 74: COMPETENCE MODELLING IN CONSULTATIO
Page 75 and 76: ROOM LIGHTING FOR VDU OF PARTIALLY
Page 77 and 78: A ERGONOMICALLY DESIGNED VDT WORKST
Page 79 and 80: l'SlINFORMATISATION ET ECLAIRAGE DA
Page 81 and 82: K1 139REVIEW OF CURRENT KNOWLEDGE:
Page 83 and 84: EXPERIENCES FROM TWO YEARS' OF AUTH
Page 85 and 86: A NEW SWEDISH STANDARD FOR MEASURIN
Page 87 and 88: CENTRAL PROGRAMME FOR BETTER VDU CO
Page 89 and 90: WÊÊÈMmMTFA AS A METRIC FOR COMMU
Page 91 and 92: U 161MEASUREMENTS OF ELF AND RF ELE
Page 93 and 94: jaTINTED GLASSES VERSUS EXERCISE FO
Page 95 and 96: THE USEFULNESS OF AN OPHTALMIC LENS
Page 97 and 98: COMPUTERIZATION AND SICKNESS ABSENC
Page 99 and 100: HUMAN INTERFACE REQUIREMENTS FOR IN
Page 101 and 102: SWEDISH STRATEGIES ON EUROPEAN ERGO
Page 103 and 104: PRÉSENTATION AlUHO-VISI iEI.l i;AU
Page 105 and 106: AuteurAuthorDate et heureHour and d
Page 115: EFFECTS OF PULSED MAGNETIC FIELDS O
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