Today, the existing regulatory and methodological documents provide no approved methodological approach to hygienic assessment of brightness and pulsation of mobile electronic devices (MEDs) with a small screen. The study was aimed to customize the current procedures used to assess brightness and pulsation of electronic devices with a large screen for hygienic assessment of brightness and pulsation of the small-sized MED screens. The design characteristics of 100 MEDs (smartphones and tablets) used by medical students in their leisure time and during training were estimated; pulsation and brightness of the MED screens were studied. The questionnaire survey of 173 medical students was performed that involved the use of the questionnaire developed by members of the Department of Hygiene, Faculty of Pediatrics, Pirogov Russian National Research Medical University; the students’ visual acuity was assessed. Two thirds of medical students (67.5%) use MEDs with the screen size exceeding the average (5.5–6.8 inches). The average brightness of every second MED is less than 50.0% of the highest possible brightness. The decrease in the MED screen brightness results in the increase of pulsation coefficient (Spearman's rank correlation coefficient –0.462 ± 0.025, p ≤ 0.05), which can worsen the conditions of visual work. Three quarters of students (76.0%) experience shortage of battery charge during the day; every second student (52.2%) uses the “dark” theme. The development of computer vision syndrome in students is influenced by the MED screen small size (Pearson's contingency coefficient 0.791 ± 0.026, p ≤ 0.05) and its low brightness (Pearson's contingency coefficient 0.781 ± 0.027, p ≤ 0.05), which confirms a sanitary legislation provision on prohibition of the use of smartphones in educational activities (for training). The use of the proposed methodological approach will make it possible to improve the efficiency of vision problem prevention in the population.