SIGNIFICANCE Digital display use has been accepted as a contributing factor to dry eye disease. Nowadays, plenty of new models of digital displays have been developed, and the differences in their nature and the ways in which they are set and used may contribute to differences in the eye-related problems they cause. PURPOSE This study aimed to analyze the differences in ocular surface, tear film, and visual fatigue parameters after reading on different digital displays, with and without initial instillation of artificial tears. METHODS Thirty-one healthy individuals ranging in age from 20 to 26 years (mean ± standard deviation, 21.26 ± 1.73 years) were included in this prospective clinical study. Subjects' ocular surface, tear film, and visual fatigue parameters were assessed after reading for 15 minutes on a laptop computer, tablet, e-reader, and smartphone with matching characteristics and a baseline measurement. Measurements were taken with and without the instillation of artificial tears before the reading tasks and included the Ocular Surface Disease Index questionnaire, the Computer Vision Syndrome Questionnaire, tear meniscus height, the Schirmer I test, noninvasive keratograph break-up time, osmolarity, bulbar redness, and pupil size. RESULTS Statistically significant differences in the Ocular Surface Disease Index, Computer Vision the Syndrome Questionnaire, tear meniscus height, the Schirmer I test, noninvasive keratograph break-up time, osmolarity, and bulbar redness were obtained when comparing the displays (P < .05). Best results were obtained with the smartphone and the e-reader. Conversely, the computer produced the highest disturbance on the ocular surface and tear film. Finally, the instillation of artificial tears revealed no statistical improvement of ocular surface or tear film parameters for the same device (P > .05). CONCLUSIONS Taking into account the clinical tests for dry eye diagnosis, the smartphone may be considered as the least disturbing display, producing lower dry eye signs and symptoms in comparison with other devices.

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Purpose This study aimed to assess the differences in blinking kinematics while reading on different digital displays and a control condition. Methods Thirty-two young healthy individuals were included in this prospective clinical study. The blinks of subjects were recorded for 150 s while reading on a laptop computer, tablet, e-reader, and smartphone and a control condition. Blinks were recorded using an eye-tracking device and were analyzed by means of image analysis to obtain a non-invasive detailed description of the blink movement. Results Blink rate decreased when reading on all displays compared to the control (p < 0.0005), although no differences were obtained amongst displays (p > 0.05). The percentage of incomplete blinks was higher with the computer compared to the control (p = 0.043), and lower with the smartphone compared to the rest of the conditions (p ≤ 0.015). Blink amplitude was smaller when reading from handheld devices compared to the control (p < 0.0005) and the computer (p ≤ 0.048). Closing and opening blink durations remained unvaried amongst conditions (p > 0.05), while opening and closing speeds were greater for the control and the computer compared to the handheld displays (p < 0.0005). Finally, contact and total blink durations were shorter during computer reading compared to the control (p = 0.004 and p = 0.017, respectively). Conclusion Blinking kinematics vary considerably amongst displays and with respect to baseline, with these differences being probably attributed to differences in the way the displays are set up and the cognitive demand of the task.

Purpose: To study the changes in anterior chamber depth (ACD), anterior chamber angle (ACA), and pupil diameter (PD) during accommodation. Methods: Eighty eyes of 80 subjects, aged 22 to 40 years, were included. The rotating Dual Scheimpflug and a Placido disc system (Galilei G4, Ziemer Ophthalmic Systems AG, Switzerland) was used to measure the changes in ACD, ACA, and PD during accommodation. ACD measurement was taken for the central zone and for 4 more positions, each in different orientation (nasal, superior, temporal and inferior), 4 mm away from the centre. ACA was measured for the whole eye as well for the nasal, superior, temporal, and inferior quadrants. These metrics were obtained for various accommodation stimuli, ranging from +1 D to -4 D in 1-D steps. Results: For a given position, the ACD did not vary significantly with accommodation. For the central ACD, the percentage of relative change between far and near vision was -4.11%. The ACA was significantly lower at the inferior, temporal, and superior positions. There was no change in the ACA of the whole eye and that of the nasal orientation. These two eye metrics were significantly lower in the superior-nasal than in the inferior-temporal region. At each vergence studied, the PD decreased significantly with accommodation. The relative change after the -4 D stimulus was -8.13%. Conclusion: ACA and PD varied significantly with accommodation, whereas no such variation of ACD was observed. Further, the anterior chamber was found to be asymmetrical, with the nasal-superior area becoming significantly shallower than the inferior temporal region. Keywords

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