[The clinical value of using a distant-image screen for reading and learning].

Objective: To investigate the effect and comfort of using a distant-image screen for reading and learning. Methods: It was a prospective cross-over study. Thirty-nine volunteers, including 13 males and 26 females, aged (26.4±4.5) years (20 to 37 years), were recruited from Beijing Tongren Hospital Affiliated to Capital Medical University in July 2021. The volunteers read the digital correction table printed on paper and displayed on a distant-image screen in a random order and rest in an interval of 2 hours. Reading speed, efficiency and accuracy of using the two devices were recorded, and the changes of logMAR vision, diopter, flicker fusion frequency and visual fatigue score after reading were calculated. Comparison of the quantitative data was performed using the paired t-test. Results: The speed, accuracy and efficiency were (41.2±11.6) digit groups/min, 80.7%±13.3% and (32.4±7.4) digit groups/min in reading on paper, (41.7±11.1) digit groups/min, 76.4%±12.6% and (31.1±6.4) digit groups/min in reading from screen, respectively. There was no significant difference in reading speed (t=-0.462, P=0.648) and reading efficiency (t=1.954, P=0.058), but there was significant difference in reading accuracy (t= 2.226, P=0.032). The logMAR visual acuity of right eye and left eye decreased by 0.014±0.032 and 0.013±0.050 after reading on paper, but increased by 0.007±0.033 and 0.007±0.036 after reading from screen, respectively. The difference was significant (right eye, t=2.592, P=0.013; left eye, t =2.154, P=0.038). The myopia degree of right eye and left eye increased by (0.07±0.29) D and (0.06±0.24) D after reading on paper, and increased by (0.01±0.29) D and (0.02±0.28) D after reading from screen, respectively. The flicker fusion frequency decreased by (0.1±1.0) Hz after reading on paper, but increased by (0.3±1.2) Hz after reading from screen. There was no significant difference (P>0.05). The subjective scale score of visual fatigue increased in both groups, with no statistically significant difference (t=1.165, P=0.251). Conclusion: The use of a distant-image screen for reading and learning does not affect the reading efficiency or increase the visual fatigue, and can avoid the decline of visual acuity caused by near viewing compared with using the printed matter.