Degree Of Visual Fatigue Research Articles

Effects of the Font Size and Line Spacing of Simplified Chinese Characters on Smartphone Readability

Abstract In this study, we explored the effects that the font size and line spacing of simplified Chinese characters had on their readability on smartphones. One hundred and fifteen participants were recruited to complete Chinese text comprehension tasks and provide user preferences on a 5.9-inch smartphone. Nine test conditions were studied, consisting of three font sizes (10-, 12- and 14-point) and three line spacing variations (1.25-F, 1.5-F and 2-F). The results showed that both font size and line spacing significantly affect reading time, but only font size significantly affects reading accuracy; font size, line spacing and the interaction between them have significant effects on the difficulty of reading and the degree of visual fatigue. Medium and large font sizes are more comfortable to read with large line spacing, while small and medium font sizes are more attractive with large line spacing. The results provide useful information for mobile text interface design.

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

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.

Investigation on Dietary Lutein Intake and Visual Fatigue in College Students

Objectives: To investigate the correlation between intake of lutein and the occurrence of visual fatigue symptoms in college students. Methods: A total of 428 college students were randomly selected to answer the questionnaires in order to study the influencing factors of visual fatigue symptoms and dietary intake of lutein. Statistical methods such as Wilcoxon test and logistic regression analysis were used for data analysis Results: The median intake of lutein in stu-dents was 2.02 mg/d. Dietary lutein was mainly provided by vegetables (93.17%). The incidence rate of visual fatigue was significantly higher in female than in male (P < 0.05). The incidence rate of visual fatigue was 76.2%, while the incidence of bulging eyes and vision loss were respectively 46.3% and 39.7% The risk factors of visual fatigue include exposure to screen light (OR = 1.635), myopia (OR = 1.902), and unhealthy habits (OR = 3.369). The protective factors of visual fatigue include male gender (OR = 0.588), outdoor activity (OR = 0.062) and lutein intake (OR = 0.507). Con-clusion: The intake of dietary lutein among the students is low, while the incidence rate of visual fatigue is high. The intake of dietary lutein is significantly correlated with the degree of visual fatigue.

SU-GG-I-49: Comparison of the Visual Fatigue with a High-Brightness Color LCD and a Monochrome LCD

Purpose: To investigate whether there are the differences among the visual fatigue of observers in the 500 cd/m2 color and the monochrome LCDs and the 170 cd/m2 color LCD (two‐mega pixels). Method and Materials: Posteroanterior chest radiographs with a lung nodule were displayed on a high‐brightness color LCD (Radiforce RX211, Eizo) with two maximum luminance settings (500 and 170 cd/m2) and a monochrome LCD (500 cd/m2, Radiforce GS220, Eizo). Six radiologic technologists aged 24.0±1.3 years were independently trained to understand various lung nodules for two hours, deemed the “Fatigue Session”. The visual fatigue of observers was evaluated in terms of the critical flicker fusion frequency (CFFF) and the visual accommodation time by use of a flicker device (Handy Flicker HF, Neitz) and an accommodation device (HS‐9E, Kowa), respectively. The measurement of the degree of visual fatigue was performed before and after the Fatigue Session for each observer. Both the decrement of the CFFF and the extension of the accommodation time were utilized as a measure of visual fatigue. The ambient lighting was set at 35 lux during all Fatigue Sessions and the measurement of visual fatigue. Results: The average visual fatigue that analyzed both the CFFF and accommodation time increased after the Fatigue Sessions. The CFFF with the 500 cd/m2 color, monochrome LCDs, and the 170 cd/m2 color LCD decreased 3.7, 3.9, and 5.6%, respectively. The accommodation times after the Fatigue Sessions with the 500 cd/m2 color, monochrome LCDs, and the 170 cd/m2 color LCD were extended by 18.5, 18.1, and 3.2%, respectively. Conclusion: In terms of the decrement of the CFFF, there were little differences among the three monitor conditions. On the other hand, the extension of the accommodation time with the 500 cd/m2 color and monochrome LCD was longer than that of the 170 cd/m2 color LCD.

Two factors in visual fatigue caused by stereoscopic HDTV images

As respects with visual fatigue caused from watching stereoscopic HDTV images, we found that when stereoscopic HDTV images were displayed within the corresponding range of depth of focus, and remained still in the depth direction, the degree of visual fatigue was almost the same as that induced by watching images displayed at the depth of the screen. However, when images were displayed outside the corresponding range of depth of focus, visual fatigue was clearly induced. Moreover, we found that even if images were displayed within the corresponding range of depth of focus, visual fatigue was induced if the images were moved in depth according to a step pulse function.