Background: Along with the rapid growth of technology its related tools such as computer, monitors and video display terminals (VDTs) grow as well. Based on the studies, the most common complaint reported is of the VDT users.Methods: This study attempts to design a proper tool to assess the Visual fatigue of the VDT users. First draft of the questionnaire was prepared after a thorough study on the books, papers and similar questionnaires. The validity and reliability of the questionnaire was confirmed using the content validity index (CVI) beside that of the Cronbach’s Coefficient Alpha. Then, a cross-sectional study was carried out on 248 of the VDT users in different professions. A theoretical model with four categories of symptoms of Visual fatigue was derived from the previous studies and questionnaires. Having used the AMOS16 software, the construct validity of the questionnaire was evaluated using the confirmatory factor analysis. The correlation co-efficiency of the internal domains was calculated using the SPSS 11.5 software. To assess the quality check index and determining the Visual fatigue levels, Visual fatigue of the VDT users was measured by the questionnaire and Visual fatigue meter (VFM) device. Cut-off points were identified by receiver operating characteristic curves.Results: CVI and reliability co-efficiency were both equal to 0.75. Model fit indices including root mean of squared error approximation, goodness of fit index and adjusted goodness of fit index were obtained 0.026, 0.96 and 0.92 respectfully. The correlation between the results measured with the questionnaire and VFM-90.1 device was −0.87. Cut‑off points of the questionnaire were 0.65, 2.36 and 3.88. The confirmed questionnaire consists of four main areas: Eye strain (4 questions), Visual impairment (5 questions) and the surface impairment of the eye (3 questions) and the out of eye problems (3 questions).Conclusions: The Visual fatigue questionnaire contains 15 questions and has a very remarkable validity and reliability. Using this questionnaire and its findings, one will be able to identify, assess and finally prevent the effective factors of VDT users’ Visual fatigue.

Background: Technology-related tools, including computers and video display terminals (VDTs), are rapidly expanding as a result of the quick growth of technology itself. Investigation on the complaints of VDT users reported Visual discomfort. This study aimed to design an appropriate tool to assess Visual fatigue of VDT users.Methods: This cross-sectional study was performed on 248 VDT users in different professions during 2011. After reading books, articles, and similar questionnaires, question banks were provided and an initial questionnaire was developed. Validity and reliability of the questionnaire were evaluated by Cronbach's alpha coefficient and content validity index (CVI). A theoretical model based on four categories of symptoms of Visual fatigue, extracted from previous studies, was designed. AMOS software was used to assess the validity of its constructs using confirmatory factor analysis and fitted parameters. Using the SPSS18, internal correlation coefficients of the domains were calculated. In order to investigate the reliability and grade the final scores of the questionnaire, Visual fatigue was simultaneously assessed by the questionnaire and the VFM-90.1 device and the results were compared. In addition, cutting points were determined by the ROC curve.Findings: A minimum CVI of 0.75, reliability coefficient of 0.755, model fit indices of RMSEA=0.026, GFI=0.96 and AGFI=0.92 were found. The correlation between the results measured with a questionnaire and VFM-90.1 was -0.87 and the cut-off points were calculated as 0.65, 2.36 and 3.88. Four main domains of the questionnaire, including eye strain (4 questions), Visual impairment (5 questions), surface related impairments of the eye (3 questions) and problems outside the eye (3 questions), were approved.Conclusion: The questionnaire contained 15 questions to assess Visual fatigue. It had excellent reliability and validity. Therefore, VDT users can easily assess their extent and level of Visual fatigue by this relatively short and simple questionnaire.

Introduction: Working with Visual Display Terminals (VDTs) can be associated with Visual complaints particularly Visual fatigue and symptoms including headache, disruption in continuing the work and ocular disorders. The objective of the present study was to determine the prevalence of Visual fatigue and its related risk factors in computer users of Kermanshah University of Medical Sciences in 2013.Materials and Methods: This descriptive-analytical study was achieved on 260 computer users. The data were collected by Visual fatigue, demographic and job questionnaires. For data analysis, Spearman, Mann-Whitney and Kruskal-Wallis tests were used.Results: The mean (SD) age of the users was 36.74 (7.74) and daily working time with VDTs was 5.85 (2.28) hours. Visual fatigue score was 2.99 (1.97), so that 32.3% of computer users had severe eye fatigue. Meanwhile, 45.4, 21.9, 32.7 and 46.2 percentage of users suffered severely from eye strain, Visual impairment, eye-surface disorder and extra-ocular problems. Visual fatigue incidence and its compliments were significantly increased with increasing of age, work experience and daily working hours with computer (p<0.05). Visual fatigue was higher in users wearing glasses than those not wearing glasses (p<0.001) and was lower in monitor to window angle of 90o than two other monitor to window positions of 0o (p=0.041) and 180o (p=0.036).Conclusion: The prevalence of Visual fatigue among computer users was very high. Visual fatigue and its serious consequences can be prevented by applying the principles of ergonomics such as regular and short breaks, looking at distant objects, blinking regularly and reducing the direct and indirect glares.

Background and aims: The most complaints of Video Display Terminals (VDT) users are Visual fatigue. Inadequate sleep quality is one of the factors that affect one's occupational performance. Since low sleep quality, Visual fatigue and inappropriate lighting cause errors and reduce accuracy in work, so the aim of this study was to determine the relationship between lighting and Visual fatigue and the relationship between Visual fatigues and sleep quality. Methods: This descriptive cross-sectional study was conducted on 191 VDT users in various occupations in 2016 and Lux meter device was used to measure the lighting. Pittsburg sleep quality and Visual fatigue questionnaires were used. The results were analyzed using SPSS software. Results: The average of eye fatigue score before and after work were 0. 72± 1. 03 and 2. 66± 2. The mean intensity of lighting was 345. 34± 274. 3 Lux and Sleep Quality Index score was 6. 29± 2. 67. There was no significant correlation between lighting and difference of Visual fatigue (P=0. 552, r=-0. 043). The relationship between eye fatigue and sleep quality score was significant (P<0. 001, r=0. 33). There was no significant relationship between lighting and sleep quality (P=0. 572, r=-0. 041). Conclusion: The results of this study showed that Visual fatigue and sleep quality have a reverse relationship. As Visual fatigue increased in VDT users, the status of sleep quality became weaker, so that Visual fatigue, along with complaints of pain, pressure, and blurred vision, increasing the number of errors during job tasks and thus disrupting the work. Therefore, in order to improve these problems, it is necessary to pay attention to the durat ion of sleep at night and the related parameters.

Background: Driver’s fatigue is a major factor contributing to the prevalence of road accidents. A vast number of city dwellers in most countries use public transport bus services to move around the city. Driver’s fatigue causes job burnout and affects the risk of a traffic accident injuring the public. Several methods have been used to date for evaluating mental fatigue; however, using questionnaires tends to be a less time-consuming and more accessible technique. The present study was therefore conducted to develop a mental fatigue questionnaire for public transport bus drivers.Materials and Methods: The study was conducted based on the criteria used for qualitative research. Semi-structured interviews were held with public transport bus drivers using probing questions and data were collected until their saturation so as to enable access to a direct description of mental fatigue by the bus drivers. Data saturation occurred with 30 interviews and sampling was then discontinued. The analysis of the interviews led to the extraction of the themes and an initial list of questionnaire items was then developed. The psychometric properties of the questionnaire were then evaluated through examining the content validity and internal consistency of the items. The content validity of the items was calculated using Lawshe’s table. A minimum CVR of 0.99 and a minimum CVI of 0.75 denoted an acceptable content validity for the items. To determine the internal consistency of the items, 200 bus drivers completed the final version of the questionnaire. The data obtained were then analyzed in SPSS-16 using Cronbach's alpha to measure the reliability of the questionnaire and considering an acceptance level of 0.7.Results: The interviews conducted at the beginning of the study with 30 drivers led to the emergence of an initial list with 26 items. A total of 9 items with a CVR less than 0.99 were omitted from the list and 17 items with adequate simplicity, clarity and correlation between them and which had a minimum CVI of 0.75 were kept. The questionnaire had a Cronbach's alpha value of 0.87 and was therefore considered a reliable tool.Conclusion: The questionnaire developed in this study has a good validity and reliability and can therefore be used to assess mental fatigue in public transport bus drivers.

Collecting self-reported data through questionnaires and surveys has long been the most commonly used tool in healthcare research. These studies provide important information concerning a population’s feelings, experiences, habits, health, and opinions. 1 Obtaining correct and accurate data from survey respondents has long been a challenge for researchers. 2 Today, there are many studies that use questionnaires as a main tool for collecting data from patients, health care professionals, and other groups. However, people become overwhelmed by the number of surveys and questionnaires they encounter in daily life, and they thus become fatigued. 1, 3 This type of fatigue is called survey fatigue or respondent fatigue, a phenomenon where individuals become tired and uninterested in answering the questions of surveys, lose their motivation to complete surveys, provide less thoughtful answers to questions, or prematurely terminate participation as a result. 4, 5 Another form of respondent fatigue can be visible as a respondent skips the questions, leaves text response fields blank, selects the default answers to the questions, or the same option is selected in a series of multiple-choice questions. 4