The aim of the present study was to evaluate the different features of such instruments and how they cause ocular fatigability.

Under the same settings and circumstances, 75 participants were asked to read the novel, "You without me?" in different formats including paper book, E-book (biscuit®, Interpark Inc., LG INNOTECK LTD, Korea) and LCD reader (iPad®, Apple Inc., United States). For every 10 minutes of reading, 10 minutes of rest was provided. After finishing the novel, the participants were asked to complete a questionnaire, and the data obtained were statistically analyzed using univariate analysis.

Compared to paper book readers (1.93), LCD readers (2.40) complained of insufficient lubrication in the eye ( p = 0.038), and experience more letter-floating illusions (1.92) than did paper book readers (1.49) ( p = 0.043). Moreover, compared to the other formats including the E-book (20%) and paper book (8%), LCD readers (72%) experienced more significant glare symptoms (n = 23) and could read at a faster rate than the other groups of readers (n = 26).

In the present study, the I-Pad caused ocular fatigability more easily than the other formats examined. No statistical significance of ocular discomfort or fatigability was observed among the different format groups. Further investigation with a greater number of age-controlled participants should be conducted prior to designing a study to determine the best format for reading.