| With the development of the information age,the network has become one of the most important ways to acquire knowledge.Every day people need to deal with large amount of reading tasks on electronic screens.Focusing on screens for prolonged periods may cause a great eye burden,which would result in searing,red,and dry eyes.Worse still,this may lead to unwanted effects-nausea,vomiting and so on.Good-design font can delay the arrival of visual fatigue to a certain extent,protecting the users' eyesight.So it's necessary for people to use reasonable fonts in e-reading.The traditional research of the fonts has proved that enlarging palace moderately in the text,increasing the thickness of the strokes of characters and adjusting text strokes can retard visual fatigue.But these principles lack experimental data support and the effect could not be quantified.In view of the shortcomings of traditional research methods,this study draws on the usability studies,combining subjective evaluation with physiological measurement.By comparing the visual fatigue degrees caused by the four main fonts in e-reading,this paper puts forward a visual fatigue degree evaluation method based on the pupil diameter.20 subjects are asked to complete the reading tasks and record their eye movement data.After that they are also required to grade their own visual fatigue degrees.The experiment results show that the visual fatigue degree caused by Song font is the least serious.Further studies indicate a strong correlation between the pupil diameter variations and visual fatigue degrees.And the higher the visual fatigue degrees,the bigger the pupil diameter variations.A mathematical model is built on visual fatigue degrees and pupil diameter variations.Designers and researchers could forecast visual fatigue degree curve in the e-reading testing via this model,which may improve their design and research. |
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