The impact of break schedules on digital eye strain symptoms and ocular accommodation during prolonged near work

This study evaluated the effects of four different break schedules on symptoms and signs of Digital Eye Strain (DES) during a 40-min reading task. Twenty-four young adults participated in four experimental conditions, performed on four different days in random order: no break, one break at 20 min, one break every 10 min and self-paced breaks. Primary outcomes included visual symptoms reported after the reading task, accommodative lag and variability during the reading task, and the near work-induced transient myopia (NITM) assessed post-task (including initial NITM and its decay). Visual symptoms were evaluated using a 10-item questionnaire, while accommodative measures were obtained with a binocular open-field autorefractor (Grand Seiko WAM-5500). Participants reported higher "eye irritation or burning" in the no-break condition compared to the 3-break (p < 0.001) and self-paced breaks conditions (p = 0.008). Eye strain was also greater in the no-break condition than in the 3-break (p = 0.04) and self-paced breaks conditions (p = 0.04). Accommodative variability showed significant effects for both break schedule (p = 0.03) and time period (p = 0.02), with greater variability observed in the no-break and 3-break conditions during the final time interval. NITM was higher in the no-break condition compared with the 3-break (p = 0.02) and self-paced breaks conditions (p = 0.02), while NITM decay was faster in the 3-break condition (p = 0.001). Accommodative lag did not differ significantly across conditions. These findings highlight the potential benefits of individualized and frequent breaks for managing DES during prolonged screen use.