Effect of Font Size and Glare on Computer Tasks in Young and Older Adults

Physical work environment in an activity-based flex office: a longitudinal case study

OBJECTIVE

This study aimed to investigate and explore Occupational Health and Safety (OHS) management, office ergonomics, and musculoskeletal symptoms in a group of office workers relocating from cell offices to activity-based flex offices (AFOs).

METHODS

The analysis was based on qualitative interview data with 77 employees and longitudinal questionnaire data from 152 employees.

RESULTS

Results indicate that there was a need to clarify roles and processes related to the management of OHS. Self-rated sit comfort, working posture, and availability of daylight deteriorated and symptoms in neck and shoulders increased after the relocation and seemed to be influenced by many factors, such as difficulties adjusting the workstations, the availability of suitable workplaces, and age, sex, and individual needs.

CONCLUSION

Research on the long-term effects of physical work environments and management of (OHS) issues after implementing activity-based flex offices is sparse. This study demonstrates the importance of planning and organising OHS issue management when implementing an AFO, and to carefully implement office ergonomics among office workers.

User experience with ultrawide curved displays: A mixed methods analysis

Due to the trend of replacing dual displays with ultrawide (UW) curved displays, we used a mixed methods analysis to investigate the user experience with UW curved displays. We conducted an experimental laboratory study that quantified user self-selected positions for three displays - 24 in. flat panel, and 34 in. and 40 in. UW curved displays. Participants were first provided with a familiarization protocol, and they then positioned the display. The self-selected UW display viewing distances were within current recommendations; however, viewing distance increased with display size, potentially challenging small work surface depths and may have been in response to feeling "overwhelmed" by larger displays. Head twist range of motion increased with display width. While all displays were within recommendations, participants commented that less head twisting was a factor in choosing the 34 in. over the 40 in. display. Practitioners should assess potential workstation limitations and the potential impact on neck twist angles when installing ultrawide displays.

Designing Combinations of Pictogram and Text Size for Icons: Effects of Text Size, Pictogram Size, and Familiarity on Older Adults' Visual Search Performance

OBJECTIVE

This study aimed to determine suitable combinations of text and pictogram sizes for older adults and investigated the visual prioritization of pictogram versus text.

BACKGROUND

Icons have become an indispensable part of application (app) design. Pictogram size and text size of icons influence the usability of apps, especially by aged users. However, few studies have investigated the influences of different pictogram and text size combinations on readability, legibility, and visual search performance for older adults.

METHOD

This study used eye-tracking technology to investigate the effects of different pictogram and text size combinations as well as familiarity on readability, legibility, and visual search performance for older adults. A 3 (pictogram size) × 3 (text size) × 2 (familiarity) repeated-measures experimental design was used.

RESULTS

The results of this study suggest that pictogram size and text size significantly affect visual search performance and that familiarity moderates the effect of text size on distribution of fixation duration proportion for text and pictograms.

CONCLUSION

Large pictogram and text sizes improved the readability and legibility of icons for older adults. Furthermore, the older adults fixated the area of text prior to pictograms when the pictogram size was larger than 72 × 72 px (1.38° × 1.38°) in the visual search task.

APPLICATION

The results of this study suggest using different combinations of pictogram and text sizes for older adults under different scenarios. The findings of this study act as practical support for designers and developers of mobile apps for older adults.

Examination of distraction and discomfort caused by using glare monitors: a simultaneous electroencephalography and eye-tracking study

Background

Since the COVID-19 pandemic started, remote work and education and digital display use have become more prevalent. However, compared with printed material, digital displays cause more eye fatigue and may decrease task performance. For instance, the reflections on the monitor can cause discomfort or distraction, particularly when glare monitors are used with black backgrounds.

Methods

This study simultaneously uses electroencephalography (EEG) and an eye-tracker to measure the possible negative effects of using a glare monitor on the illegibility of sentences.

Results

The experiment results showed no difference in reading time and subjective illegibility rating between glare and non-glare monitors. However, with glare monitors, eye fixation when reading lasted longer. Further, EEG beta (15-20 Hz) power variations suggested that the participants were less engaged in the reading task when a glare monitor was used with a black background.

Conclusions

These results indicate that the negative effects of using a glare monitor are subtle but certainly present. They also show that physiological measures such as EEG and eye tracking can assess the subtle effects in an objective manner, even if behavioral measures such as subjective illegibility ratings or reading time may not show the differences.

Analysis of real-world visual ergonomics at the visual display unit

INTRODUCTION

In this interventional study, the ergonomic workplace set-up and the impact of character size on subjectively estimated working productivity and computer vision syndrome (CVS) were evaluated in the field.

METHODS

The number of displays and their size, resolution, surface structure, position in the room and relation to the eye were evaluated for 152 units. CVS was assessed using the CVS-Questionnaire. Habitually used character size for an uppercase E was recorded and compared to the ISO 9241-303:2011, national standards (e.g., ANSI/HFES 100-2007) and national guidelines (e.g., German DGUV Information 215-410). In case of failure to comply with these standards, character size was increased to 22 angular minutes to reach the recommended ranges. Reasons for returning to former or smaller character sizes were recorded, and subjectively perceived changes in productivity were estimated by the participants using a visual analogue scale before and 2 weeks after the intervention using a questionnaire.

RESULTS

The average visual display unit consisted of two non-glare (matt) 24″ widescreen monitors that were located approximately 73 cm (primary) and 76 cm (secondary) from the eyes. The mean (SD) habitually set character size was 14.29 angular minutes (3.53) and therefore both statistically and clinically significantly too small compared with ISO 9241-303:2011 (p < 0.001). Increasing the character size to 22 angular minutes produced a 26% reduction in subjectively rated productivity (p < 0.001). No significant correlation between character size and symptoms of CVS was demonstrated.

CONCLUSIONS

In the workplaces investigated, recommendations for character size were not adhered to. This resulted in a reduction in productivity and was not compatible with some of the work requirements, for example, obtaining a broad overview of a spreadsheet.

How to design font size for older adults: A systematic literature review with a mobile device

With the global society aging, it is necessary to investigate suitable font size based on reading time/speed, readability and legibility for older adults. This study used a systematic review of previous and existing relevant research on font size for older adults and research on the psychophysics of reading and analyzed the outcomes based on reading time/speed, readability, legibility and the usability evaluation methods employed. Studies were selected from databases GOOGLE SCHOLAR, WEB OF SCIENCE, PUBMED, and SCIENCE DIRECT. An inclusion criterion was used to remove duplicates and avoid inconsistencies. Results suggest that older adults preferred larger font sizes. However, there exists a critical size at which readability declines. Inconsistencies in evaluation methods and experimental procedures were observed in the selected articles. This study suggested a reusable catalog of usability evaluation methods, eye tracking for user testing and a questionnaire for inquiry as suitable usability evaluation methods, a uniform metrics to measure font size (visual angle of font) in arcminutes and parameters to consider when investigating font size for older adults to ensure consistency in future studies.

Learning Experience Design in Health Professions Education: A Conceptual Review of Evidence for Educators

OBJECTIVES

The increasing use of online resources in emergency medicine (EM) education has driven demand for higher quality resources. Learning experience design (LED) is the study of how electronic user interfaces impact learner outcomes. We sought to summarize the evidence for LED principles to inform creation of EM educational resources.

METHODS

We performed scripted searches of MeSH terms, PubMed keywords, and hand tracings. Inclusion criteria were controlled studies using light-emitting diode or liquid crystal display monitors with Latin-based languages. Cathode ray tube (CRT) monitors were excluded because of the user experience confounders.

RESULTS

Thirty-two articles met inclusion criteria. Overall, 14-point size significantly improved legibility compared to smaller font sizes. Similarly, Verdana and Arial typefaces significantly improved legibility compared to Times New Roman typeface. Verdana also significantly decreased subjective mental workload and visibility difficulty ratings and required the least eye movement of any typefaces tested. Positive polarity (dark text on light background) significantly improved reading outcomes across many measurements over negative polarity. There was higher character identification accuracy with higher luminance. Text effects (e.g., italics), interword and interletter spacing, and page presentation are among variables with mixed or minimal evidence.

CONCLUSION

Learning experience design principles significantly impacted reading and learning outcomes in laboratory settings. No studies evaluated classroom outcomes. Recommendations for electronic learning environments are 14-point font with Verdana or Arial typeface with positive polarity (dark letters on light background). We recommend increasing screen brightness slightly. EM educators may significantly improve the speed and accuracy of learning written material by espousing evidence-based LED principles.

Effects of environmental illumination and screen brightness settings on upper limb and axial skeleton parameters: how do users adapt postures?

79% of smartphone users carry their phone 22 hours a day. In this context, the main task worldwide, texting, is performed under a wide range of light and position conditions. The aim of this study was to test the effects of environmental illumination and screen brightness settings on upper limb and axial skeleton parameters. Twelve subjects performed three trials of texting under three experimental positions, two screen luminance settings and three environmental light conditions. 3 D axial skeleton and upper limb angles, smartphone orientation and face-to-smartphone distance were used as dependent variables. High environmental illumination and/or low screen brightness resulted in an increase in interaction time and a reduction in the face-to-smartphone distance by approximately 10%. Subjects attempted to compensate for the unfavourable effects of such light conditions by adopting postures rated 5 in the Rapid Upper Limb Assessment, indicating an increased risk of developing musculoskeletal disorders. Practitioner's summary: The purpose of the study was to quantify the joint angles of the upper body in experimental conditions that represent daily life. Postures were influenced by ambient illumination and display brightness. The most harmful postures were observed when the display brightness was minimum, and the ambient light was similar to a sunny day. Abbreviations: ST: seated with table; SWT: seated without any support; STA: standing; 0L: in the dark, no light; AL: ambient light; SL: strong light; BrightMin: minimum display brightness; BrightMax: maximum display brightness (BrightMax); ISB: International Society of Biomechanics; RULA: rapid upper limb assessment; MSDs: musculoskeletal disorders.

Ocular symptoms associated with digital device use in contact lens and non-contact lens groups

PURPOSE

Previous reports indicate that "eye fatigue" occurs in roughly 60 % of the adult population using digital devices and may negatively impact quality of life. However, the construct of eye fatigue remains poorly understood. The goal of this study was to quantify the relationship among symptoms most frequently associated with eye fatigue in those using digital devices.

METHODS

Six hundred and two soft contact lens (SCL) wearers and 127 non-contact lens (non-CL) wearers who reported using digital devices at least 4 hours per day completed a questionnaire assessing the frequency and severity of ten symptoms commonly associated with digital device-related eye fatigue. Subjective ratings were made separately for each symptom using unipolar, five-point Likert scales.

RESULTS

From the initial pool of respondents, 89 % of the SCL wearers reported experiencing eye fatigue more than once per month, while over 60 % reported more than once per week. Notably, eye fatigue frequency did not differ between the soft contact and non-contact lens groups. Although eye strain/pain, dryness, and tired eyes were the most frequently endorsed symptoms by both groups, only dryness and eye irritation were significant factors that discriminated the SCL from the non-CL wearers on the basis of frequency and severity. Principal component analysis indicated that eye strain/pain, soreness, tired eyes, and headaches may comprise a "primary sensations" factor, whereas burning, eye irritation, tearing and dryness comprise a "secondary or surface sensations" factor, and blurred/double vision and words move/float comprise a "visual sensations" factor. Confirmatory factor analysis (CFA) of frequency and severity ratings for SCL wearers yielded excellent fits (RMSEA = 0.046 and 0.050, respectively) with construct reliabilities ranging from 0.729 to 0.824.

CONCLUSION

Frequent and severe eye fatigue is highly prevalent among both soft contact lens and non-contact lens wearers. Those utilizing SCL do not experience symptoms at higher frequency or severity. Key descriptors of digital eye fatigue have been identified and may then be used to help identify and evaluate specific causative, palliative, or ameliorating factors.

How People with Low Vision Achieve Magnification in Digital Reading

SIGNIFICANCE

Digital reading displays provide opportunities for enhancing accessibility of text for low vision. How are these displays used by people in their daily lives?

PURPOSE

Subjects responded to an online survey concerning their vision history, reading technology, display preferences, and reading habits. Here, we report on findings concerning acuity and magnification.

METHODS

The survey asked subjects to arrange a text passage for typical reading and to report viewing distance, screen dimensions, and the number of characters per line. Seventy-five adult subjects (most with early-onset low vision, few with central field loss) completed all survey questions relevant to the analysis of acuity and magnification. Mean acuity was .92 logMAR (range, 0.1 to 1.6), and mean age was 44.8 years (range, 18 to 71 years). Twelve normally sighted controls reported the same information while viewing the passage on cell phones, tablets, and computers.

RESULTS

The controls had a mean viewing distance of 38.7 cm and a mean x-height of 1.38 mm. For all three types of devices, angular x-height was 0.21° (close to laboratory estimates of the critical print size for reading). Low vision subjects showed decreasing viewing distance and increasing print size with larger values of logMAR acuity. Most of the low vision subjects achieved their desirable magnification by a combination of reduced viewing distance and increased physical letter size. The majority (54 of 75) relied more on letter-size magnification. Relative to the controls, regression analysis revealed that a typical low vision subject with logMAR acuity of 1.0 reduced viewing distance by a factor of 2.8 and enlarged physical print size by a factor of 6.

CONCLUSIONS

Our survey shows that people with a wide range of acuities are engaged in digital reading. Our subjects achieved desirable magnification primarily by enlarging physical character size and to a lesser extent by reducing viewing distance.

The pitfalls of the traditional office ergonomics model in the current mobile work environment: Is visual ergonomics health literacy the remedy?

Mobile technology has revolutionised how we work. It is now relatively easy to work anywhere and anytime, but this has placed the onus is on mobile (or flexible) workers to set up their own work environment for comfort and ease of use. Vision is an important driver of posture, and hence visual ergonomics principles are integral for setting up digital devices. If mobile workers do not have visual ergonomics knowledge, or are unable to apply visual ergonomics knowledge to appropriately set up their work environment, then they are at risk of developing visual-related occupational health issues due to exposure to adverse physical work environments. To address this potential health care issue, we propose the introduction of Visual Ergonomics Health Literacy. This would provide mobile workers (including school children) with the knowledge and skills to set up their work environment for comfort and ease of use, wherever they work. It is important to address this issue now before we have a widespread epidemic of discomfort and injury from not applying sound visual ergonomics principles to work environments.

Larger Chinese text spacing and size: effects on older users’ experience

With declining vision ability, character spacing and size on smartphones designed for the general population are not accessible for older adults. This study aimed to explore how larger Chinese character spacing and size affect older adults’ user experience (UX). An orthogonal experiment was conducted. The optimal range of font size (FS), word spacing (WS) and line spacing (LS) were proposed utilising subjective evaluations to investigate the correlation of eye movement data with participants perceived UX. The results showed that improvement in different aspects of UX varied when FS, WS and LS increased. Overall, participants preferred larger FS, WS and LS, however, the larger FS, WS and LS values are more likely to cause errors and slower reading speed. These results suggest that the distinct combination of size and spacing depends on the motivation, needs and situation of older people when reading on a smartphone. These findings will help designers to provide better design for the older people.

Effect of unifocal versus multifocal lenses on cervical spine posture in patients with presbyopia

Significance. There are many environmental considerations which may or may not lead to the development of faulty cervical mechanics. The design of near-vision lenses could contribute to the development of such cervical dysfunction and consequently neck pain. Decision-making regarding the proper type of lens prescription seems important for presbyopic individuals. Purpose. To investigate the effect of unifocal and multifocal lenses on cervical posture. Methods. Thirty subjects (18 females and 12 males) participated in the study with an age range from 40 to 64 years. Each subject wore consequently both unifocal and multifocal lenses randomly while reading. Lateral cervical spine X-ray films were taken for each subject during each lens wearing. X-ray films were analyzed with digital software (AutoCAD 2D version 22) to measure segmental angles of the cervical vertebrae (occiput/C1, C1/C2, C2/C3, C3/C4, C4/C5, C5/C6, C6/C7, C3/C7, C0/C3, and occiput/C7). Results. Higher significant extension angles were observed in the segments C0/C7, C1/C2, C5/C6, C6/C7 and C3/C7 (p < 0.05) during multifocal lens wearing, in contrast to higher flexion angles between C3/C4 and C4/C5 (p < 0.05) when wearing unifocal lenses. Conclusion. Multifocal lens spectacles produce increased extension in the cervical vertebrae angles when compared with the use of unifocal lenses.

Viewing distance and eyestrain symptoms with prolonged viewing of smartphones

BACKGROUND

This paper investigates viewing distances and eyestrain symptoms in young adults reading from a smartphone for 60 minutes.

METHODS

A survey related to common asthenopic (eyestrain) symptoms was administered to subjects before and after they read an extract from a novel on a smartphone for 60 minutes. Subjects rated their symptoms on a scale from zero (not at all) to four (extremely). The viewing distance to the smartphone was measured on a photograph taken of the subject every minute. Each subject used the same smartphone and read the same text.

RESULTS

Subjects were 18 young adults (mean age: 21.5 ± 3.3 years) with self-reported good health, normal visual acuity and no accommodative or binocular vision disorders. The mean viewing distance while using a smartphone over 60 minutes was 29.2 ± 7.3 cm. The viewing distance was significantly greater during the first, second and fifth 10-minute time periods (30.6 ± 7.2 cm, 29.7 ± 7.3 cm and 28.9 ± 8.5 cm, respectively) than during the final 10-minute time period (27.8 ± 7.7 cm) (Wilcoxon, p = 0.023, 0.02 and 0.04, respectively). The total symptom score was significantly greater post-experiment (score = 8.06) than pre-experiment (score = 3.56) (Wilcoxon, p < 0.001). Symptoms of tired eyes, uncomfortable eyes and blur increased significantly after 60 minutes of smartphone use (Wilcoxon, p < 0.05). There was a significant correlation between change in total symptom score and change in viewing distance (ρ = -0.51; p = 0.03). The only single symptom that correlated with a change in viewing distance was 'uncomfortable eyes' (ρ = -0.52, p = 0.03).

CONCLUSION

Viewing distances are closer and eyestrain symptoms are greater after reading from a smartphone for 60 minutes. The viewing distances measured were closer than those previously reported in the literature.