Visual Quality, Motility Behavior, and Retinal Changes Associated with Reading Tasks Performed on Electronic Devices

Background: The purpose of this study was to objectively evaluate visual discomfort using an eye tracker and aberrometer after a 21-min reading session on an iPad and an Ebook. Additionally, retinal changes were analyzed using optical coherence tomography (OCT). Methods: A total of 31 young subjects (24 ± 4 years) participated in this study. They read for 21 min on an Ebook and for another 21 min on an iPad under controlled lighting conditions while their eye movements were monitored using an eye tracker. Aberrometry and retinal OCT measurements were taken before and after each reading session. Parameters such as pupil diameter, fixations, saccades, blinks, total aberration, high-order aberration, low-order aberration, and central and peripheral retinal thickness in the nine early treatment diabetic retinopathy study (ETDRS) areas were measured for each reading situation. Statistical analysis was performed on the collected data. Results: No statistically significant differences (p > 0.05) between the two devices were observed in terms of the different types of eye movements or the changes in retinal thickness. However, the aberrometric analysis showed variations in post-reading situations depending on the device used. Conclusion: Reading speed and visual discomfort resulting from electronic device usage can be objectively assessed using an eye tracker and aberrometer. Additionally, changes found in central and peripheral retinal thickness between the two devices and the baseline measurements were not significant and remained relatively stable

Optical and motor changes associated with lighting and near vision tasks in electronic devices

Purpose: To assess optical and motor changes associated with near vision reading under different controlled lighting conditions performed with two different types of electronic screens. Methods: Twenty-four healthy subjects with a mean age of 22.9±2.3 years (18-33) participated in this study. An iPad and an e-ink reader were chosen to present calibrated text, and each task lasted 5 minutes evaluating both ambient illuminance level and luminance of the screens. Results:Eye-tracker data revealed a higher number of saccadic eye movements under minimum luminance than under maximum luminance. The results showed statistically significant differences between the iPad (p=0.016) and the e-ink reader (p=0.002). The length of saccades was also higher for the minimum luminance level for both devices: 6.2±2.8 mm and 8.2±4.2 mm (e-ink max vs min), 6.8±2.9 mm and 7.6±3.6 mm (iPad max vs min), and blinking rate increased significantly for lower lighting conditions. Conclusions: Performing reading tasks on electronic devices is highly influenced by both the configuration of the screens and the ambient lighting, meanwhile, low differences in visual quality that are transient in healthy young people, were found

Effect of Display Polarity on Amplitude of Accommodation and Visual Fatigue

This study aimed to assess the changes in the amplitude of accommodation under different display polarities and ascertain the effect of display polarities on visual fatigue. Thirty subjects randomly underwent a reading task for 30 minutes with both positive and negative display polarities. The amplitude of accommodation was measured, and subjects were required to complete a subjective symptoms questionnaire; both before and after the reading task. The amplitude of accommodation and visual fatigue symptoms were significantly reduced after the reading task, with both display polarities. Keywords: Display polarity; amplitude of accommodation; visual fatigue eISSN: 2398-4287 © 2023. The Authors. Published for AMER & cE-Bs by e-International Publishing House, Ltd., UK. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer–review under responsibility of AMER (Association of Malaysian Environment-Behaviour Researchers), and cE-Bs (Centre for Environment-Behaviour Studies), College of Built Environment, Universiti Teknologi MARA, Malaysia. DOI: https://doi.org/10.21834/ebpj.v8i24.461

Digital eye strain:Prevalence, measurement and amelioration

Digital device usage has increased substantially in recent years across all age groups, so that extensive daily use for both social and professional purposes is now normal. Digital eye strain (DES), also known as computer vision syndrome, encompasses a range of ocular and visual symptoms, and estimates suggest its prevalence may be 50% or more among computer users. Symptoms fall into two main categories: those linked to accommodative or binocular vision stress, and external symptoms linked to dry eye. Although symptoms are typically transient, they may be frequent and persistent, and have an economic impact when vocational computer users are affected. DES may be identified and measured using one of several available questionnaires, or objective evaluations of parameters such as critical flicker–fusion frequency, blink rate and completeness, accommodative function and pupil characteristics may be used to provide indices of visual fatigue. Correlations between objective and subjective measures are not always apparent. A range of management approaches exist for DES including correction of refractive error and/or presbyopia, management of dry eye, incorporating regular screen breaks and consideration of vergence and accommodative problems. Recently, several authors have explored the putative role of blue light-filtering spectacle lenses on treating DES, with mixed results. Given the high prevalence of DES and near-universal use of digital devices, it is essential that eye care practitioners are able to provide advice and management options based on quality research evidence

Human engineering design criteria study Final report

Human engineering design criteria for use in designing earth launch vehicle systems and equipmen

The effects of blue light from digital displays on visual fatigue

With the ever-increasing viewing time of digital displays, the potential effects of blue light emitted from these displays on eye health and eye fatigue are a real concern. This study presents a literature review of six laboratory studies conducted between 2014 and 2022 on the effect of using filters to attenuate the harmful effects of blue light. The review delves into smartphone and computer screen effects, recent literature reviews on blue light, and potential hazards associated with short-wavelength light. Although the majority of the studies recommended blue light filters, only three of the six laboratory studies (Shi et al. 2021, Tu et al. 2021, Lin et al. 2017) found significant positive effects. A pilot study was conducted with six participants, focusing on the immediate effects of blue light exposure from an 18-inch screen of a laptop computer, while playing a graphic-based and a text-based game with three filter conditions, no-filter, an eyeglass filter, and a digital filter. Eye fatigue symptoms of tired eyes, sore eyes, dry eyes, and blurred vision showed a reduction of perceived ratings when blue light filters were used. Symptoms of tired eyes, and dry eyes reached a significant level of p-value ,\u3c 0.5 improvement over no filter. The digital filter, which has not been tested before for computer screens, provided a statistically significantly better rating than the eyeglass filter. While the results suggest an improvement for those using blue light filter technologies and may help to advocate for more blue light blocking technology in workplace design, the overall conclusion underscores the ongoing need for comprehensive research, considering limitations such as the small sample size of the pilot study and the absence of long-term effects research

An Investigation of Visual Fatigue in Elementary School Students Resulting from Reading e-books

[[abstract]]Screen-based reading with e-books, which leverages technology in order to create pertinent learning experiences for all students, has become more acceptable to digital natives. Notably, before e-books are widely adopted in academic learning, the visual burden of students during reading activities should be considered. This investigation thus examines how reading-related factors affect visual fatigue incurred when reading both e-books and paper-based books through an experiment conducted on 24 elementary school students. The results showed that the different reading materials have no significant difference in terms of affecting students’ levels of visual fatigue; that is, reading material seems inconsequential with regard to changes in the degree of visual fatigue. Furthermore, another result found that long duration reading led visual to more burden, which also mean that long periods of reading without proper rest should be avoided. As this study of the foundation of visual fatigue reveals, the findings can be as references beneficial for integrating e-books into instruction and providing suggestions for the use of e-books in education. Therefore, we suggest that future studies should consider visual fatigue as important factors in e-book learning activity to promote their more potential benefits with regard to student learning.[[notice]]補正完

TFOS lifestyle: Impact of the digital environment on the ocular surface

Eye strain when performing tasks reliant on a digital environment can cause discomfort, affecting productivity and quality of life. Digital eye strain (the preferred terminology) was defined as “the development or exacerbation of recurrent ocular symptoms and/or signs related specifically to digital device screen viewing”. Digital eye strain prevalence of up to 97% has been reported, due to no previously agreed definition/diagnostic criteria and limitations of current questionnaires which fail to differentiate such symptoms from those arising from non-digital tasks. Objective signs such as blink rate or critical flicker frequency changes are not ‘diagnostic’ of digital eye strain nor validated as sensitive. The mechanisms attributed to ocular surface disease exacerbation are mainly reduced blink rate and completeness, partial/uncorrected refractive error and/or underlying binocular vision anomalies, together with the cognitive demand of the task and differences in position, size, brightness and glare compared to an equivalent non-digital task. In general, interventions are not well established; patients experiencing digital eye strain should be provided with a full refractive correction for the appropriate working distances. Improving blinking, optimizing the work environment and encouraging regular breaks may help. Based on current, best evidence, blue-light blocking interventions do not appear to be an effective management strategy. More and larger clinical trials are needed to assess artificial tear effectiveness for relieving digital eye strain, particularly comparing different constituents; a systematic review within the report identified use of secretagogues and warm compress/humidity goggles/ambient humidifiers as promising strategies, along with nutritional supplementation (such as omega-3 fatty acid supplementation and berry extracts)

VDT workplace design and effects on muscle disorders and eye strain among students at an educational institute

The advancement of information technology encouraged schools, universities and other educational institutions to use visual display terminal (VDT) in conducting lectures rendering services and developing various systems. The use of personal computer (PC) and laptops are common among students. Classrooms are equipped with liquid crystal display (LCD) screens for lecturers to display their lectures for students. Many cases have not been reported because of lack of awareness and understanding on ergonomic. However, Poor ergonomics of the physical environment of VDT can cause musculoskeletal disorders (MSDs); the inappropriateness of school design may influence student achievement negatively. The viewing distance and position of the screens have been found as the main factors causing MSDs. The students’ satisfactions on VDT used in the education institute were determined. The effects of VDT workplace design parameters on muscle disorder and eye strain among students were determined. Ergonomically positions of VDT for safer and comfortable use among students were proposed. Data obtained from 215 LCD projector users and 103 desktop monitor users were analyzed using frequency tables, one sample t-test and Spearman’s rank order correlation coefficient. The frequency analysis for the level of satisfaction among LCD projector users showed that most of the users (88.4%) were satisfied with the viewing distance, and were least satisfied with the lighting(51.6%). For the monitor user, the users were highly satisfied with user/ screen position (80.6%) and least satisfied with the viewing distance (61.2%). Most of the LCD projector users (36.7%), experienced eye pain while performing study tasks on the projector screen, and the least pain were for head pain (22.8%). Most of the desktop monitor users (54.9%) were experienced head pain while performing study tasks on the monitors, and only (32%) experienced back pain. The relationship between the level of satisfaction for physical environment and MSDs was determined using Spearman’s rank order correlation coefficient. Results showed that, there were a significant and negative relationship between satisfaction of lighting and the level of back pain (rs = - 0.213, p < 0.001), head pain (rs = - 0.266, p < 0.001), neck pain (rs = - 0.119, p < 0.034) and eye pain (rs = - 0.292, p < 0.001) levels. Significant relationships were found between the level of distance satisfaction and the level of back pain (rs = - 0.148, p < 0.01) and eye pain (rs = - 0.151, p < 0.04). The results of association between satisfaction of position and MSDs pain indicated that only the relationship between satisfaction of position and the eye pain (rs = - 0.151, p < 0.005) was significant and negative. The results implied that the eye is the part of the body which is affected by all the other variables (lighting, distance, and position), but particularly more affected by problems with lighting in the study hall. In conclusion, this study has demonstrated that there is a lack of satisfaction with respect to some items within the physical environment, and there were MSDs disorders associated with VDT use, especially the lighting. These all likely to play a significant role in affecting the user’s health, and subsequently their performance. Thus providing enough lighting sources above the students and nearby the ( monitor/ p- screen), added to the windows in the classrooms and libraries. Also, ensure the proper distance like an arm's length for monitor users and (2 to 10 ) meters for the presentation screen users added to the students position directly in front of the monitor or p- screen with considering the study hall design ( sloped or flat) to provide viewing angle ( 0° to -20°), which allow the students to read the text at or slightly below eyes level, all of those are suggested to reduce the MSDs among UPM students

Curved Displays, Empirical Horopters, and Ergonomic Design Guidelines

Department of Human Factors EngineeringVisual display products should be comprehensively evaluated from the perspectives of productivity, safety, and well-being. Curved display products are known to provide advantages. Although previous studies found that curved displays increase visual task performance, reduce visual fatigue, and improve the watching experience, these studies did not comprehensively examine the effects of display curvature. Moreover, they used low-fidelity curved screens that may not effectively reflect actual curved displays. The purpose of this thesis was to develop ergonomic design guidelines for determining appropriate display curvatures, considering the productivity, safety, and well-being of visual display terminal (VDT) users. Two studies on monitors and one study on TVs were conducted for this goal. In Study 1, the effects of the display curvature, display zone, and task duration on visual task performance and visual fatigue during a visual search task on a 50-inch multi-monitor were investigated. In Study 2, the effects of the display curvature and task duration on visual task performance, visual fatigue, and user satisfaction during a proofreading task on a 27-inch monitor were investigated, and the associations between ergonomic evaluation elements were then examined. Prediction models of visual fatigue and user satisfaction were subsequently developed. In Study 3, the effects of the display curvature, viewing distance, and lateral viewing position on presence, visual comfort, and user satisfaction during a TV watching task on a 55-inch TV were examined, and the importance of six viewing experience elements affecting user satisfaction was revealed. Finally, ergonomic design guidelines for curved displays were suggested. Based on the results of studies 1 and 2, an appropriate rest-break time was ecommended, taking into account visual task performance and visual fatigue. Study 1 examined the effects of the display curvature (400 R, 600 R, 1200 R, and flat), display zone (five zones), and task duration (15 and 30 min) on legibility and visual fatigue. A total of 27 participants completed two sets of 15-minute visual search tasks with each curvature setting. The 600 R and 1200 R settings yielded better results compared to the flat setup regarding legibility and perceived visual fatigue. Relative to the corresponding center zone, the outermost zones of the 1200 R and flat settings showed a decrease of 8%???37% in legibility, whereas those of the flat environment showed an increase of 26%???45% in perceived visual fatigue. Across curvatures, legibility decreased by 2%???8%, whereas perceived visual fatigue increased by 22% during the second task set. The two task sets showed an increase of 102% in the eye complaint score and a decrease of 0.3 Hz in the critical fusion frequency, both of which indicated a rise in visual fatigue. To sum up, a curvature of around 600 R, central display zones, and frequent breaks were recommended to improve legibility and reduce visual fatigue. Study 2 examined the effects of the display curvature and task duration on proofreading performance, visual discomfort, visual fatigue, mental workload, and user satisfaction. Fifty individuals completed four 15-min proofreading tasks at a particular curvature setting. Five display curvatures (600 R, 1140 R, 2000 R, 4000 R and flat) and five task durations (0, 15, 30, 45, and 60 min) were incorporated. The mean proofreading speed at its highest when the display curvature radius was equal to the viewing distance (600 R). Across curvatures, speedaccuracy tradeoffs occurred with proofreading, as indicated by an increase of 15.5% in its mean speed and a decrease of 22.3% in its mean accuracy over one hour. Meanwhile, the mean perceived visual discomfort, subjective visual fatigue, and mental workload increased, by 54%, 74%, and 24% respectively, during the first 15-min of proofreading. A decrease of 0.4 Hz in the mean critical fusion frequency during the first 15 min and a reduction in the mean blink frequency also indicated increases in visual fatigue and mental workload. The mean user satisfaction decreased by 11% until 45 min. A segmented regression model, in which perceived visual discomfort was used as a predictor, attributed 51% of the variability to visual fatigue. To sum up, a curvature of 600 R was recommended for speedy proofreading. Moreover, the breakpoint was observed be flexible, depending on VDT task types. These findings can contribute to determining ergonomic display curvatures and scheduling interim breaks for speedy but less visually fatiguing proofreading. Study 3 examined the effects of the display curvature, viewing distance, and lateral viewing position on the TV watching experience. The watching experience was assessed regarding the spatial presence, engagement, ecological validity, negative effects, visual comfort, image quality, and display satisfaction. Four display curvatures (2.3 m, 4 m, 6 m, and flat), two viewing distances (2.3 m and 4 m), and five lateral viewing positions (0 cm, 35 cm, 70 cm, 105 cm, and 140 cm) were evaluated. Seven pairs of individuals per curvature watched ten 5 min videos together, each time at a different viewing distance and lateral viewing position. Spatial presence and engagement increased when the display curvature approached the given viewing distance. Regardless of display curvature and viewing distance and TV watching experience factors, except negative effects, were degraded at more lateral viewing positions. Engagement could effectively explain the display satisfaction. These findings can contribute to enhancing TV watching experiences by recommending specific levels of display curvatures, viewing distances, and lateral viewing positions, as well as providing information on the relative importance of each watching experience element. This work suggested ergonomic design guidelines for curved displays. In Study 1, a curvature of approximately 600 R, central display zone, and frequent breaks were proposed to improve legibility and reduce visual fatigue during visual search tasks at the viewing distance of 500 mm. In Study 2, a curvature radius of 600 R and a minimum 15-minute break interval were proposed for a speedy proofreading task, at the viewing distance of 600 mm. In Study 3, a display radius of curvature similar to the viewing distance was recommended to improve the viewing experience. These results support that a curved display is ergonomically more beneficial when the display curvature approaches the empirical horopter. A relatively short 15-minute rest-time interval was suggested, considering the decrease of task accuracy and the increase of visual fatigue in studies 1 and 2. Two regression models were selected in Study 2 regarding predictive accuracy. They accounted for 70.4% of subjective visual fatigue variability and 60.2% of user satisfaction variability. Although this work was performed using relatively higher-fidelity mock-ups than previous studies, it is necessary to verify the findings with actual curved display products in the future. Furthermore, various tasks (e.g., word processing, graphics design, and gaming) and personal characteristics (e.g., presbyopia, gender, visual acuity, and product experience) should be considered to generalize the results of this thesis. These results can contribute to determining the ergonomic display curvature in consideration of productivity, safety, and well-being, and prioritizing elements of the visual fatigue and user satisfaction resulting from VDT work.ope