The influences of smartphone use on the status of the tear film and ocular surface

Abstract

Purpose: To investigate the influences of smartphone use on ocular symptoms, status of the tear film, and oxidative stress indices in the tears and at the ocular surface.

Methods: Eighty healthy volunteers were enrolled in the study. Subjective symptoms and asthenopia were evaluated using the ocular surface disease index (OSDI), visual analogue scale (VAS), and computer vision syndrome (CVS) score before and after smartphone or computer display (control) use. The status of the tear film was evaluated using fluorescein film break-up time (FBUT), non-invasive keratograph break up time (NIKBUT), Schirmer score, keratoepitheliopathy (KEP), and tear meniscus height (TMH). Oxidative stress markers in the tear film including hexanoyl lysine (HEL), 4-hydroxy-2-nonenal (4-HNE), malondialdehyde (MDA), and 8-oxo-2'-deoxyguanosine (8-OHdG) in the tear film were measured using ELISA. Reactive oxygen species (ROS) at the ocular surface were measured through 2',7'-dichloro-dihydrofluorescein diacetate. All measurements were conducted at baseline, and after use for 1 and 4 h.

Results: All parameters showed no significant group-wise differences at baseline. Scores of OSDI, VAS, fatigue, burning sensation, and dryness showed significant increases after 1 and 4 h of smartphone use compared with those at baseline (all P < 0.05). The smartphone group showed higher OSDI, fatigue, burning, and dryness scores than the control group at 4 h. Smartphone use showed significantly decreased FBUT and NIBUT at 4 h than those at baseline (P < 0.01). In the smartphone group, the concentration of HEL significantly increased at 4 h compared with that at baseline and 1 h (P < 0.01). Both groups showed increased ROS with higher value in the smartphone group versus the control group at 4 h (P < 0.01).

Conclusions: Smartphone use could not only aggravate subjective symptom indices such as the OSDI, VAS, and CVS but also induce tear film instability and oxidative stress indices in the tears and at the ocular surface.

Fig 1. Flow chart showing subject enrollment, allocation, follow up, and analysis.

Fig 2. Changes in the ocular surface disease index (OSDI) scores.

OSDI total (A), OSDI symptom (B), OSDI visual function (C), and OSDI trigger (D). *P < 0.05 versus baseline. **P < 0.05 versus 1 h. ^†P < 0.05 between the two groups.

Fig 3

Changes in visual analogue scale (A) and computer vision syndrome scores including fatigue (B), burning (C), dryness (D), blurred vision (E), and dullness (F). *P < 0.05 versus baseline. **P < 0.05 versus 1 h. ^†P < 0.05 between the two groups.

Fig 4

Changes in tear break up time (TBUT, A), non-invasive kertograph break up time (NIKBUT, B), Schirmer test (C), keratoepithelioapthy (KEP, D) and tear meniscus height (TMH, E). *P < 0.05 versus baseline. **P < 0.05 versus 1 h.

Fig 5

Concentrations of hexanoyl lysine (HEL, A), 4-hydroxy-2-nonenal (4-HNE, B), malondialdehyde (MDA, C) and 8-oxo-2’-deoxyguanosine (8-OHdG, D) in the tear film. * P < 0.05 versus baseline. ** P < 0.05 versus 1 h.

Fig 6. Reactive oxygen species production in the conjunctival epithelium afater smartphone use measured through 2’,7’-dichlorodihydrofluorescein diacetate.

*P < 0.05 versus the baseline value. ^†P < 0.05 between the two groups.