Abstract
Purpose :
Smartphone use is now ubiquitous and is associated with eye discomfort, but there is little information regarding aetiology of these symptoms. This study examined the effects of 60 minutes smartphone use on ocular symptoms, tear function, blinking and binocular vision.
Methods :
Twelve young adults (mean age: 18.9 ± 1.5 years, range 18-23; 9 females) with normal vision, and without dry eye, accommodative or binocular vision disorders completed this cross-sectional observational pilot study. Contact lens wearers did not wear lenses 48 hours prior to the study. Participants read an extract from a novel on a smartphone for 60 minutes. The following measures were conducted prior to the reading task and after 60 minutes of reading: eye strain and ocular surface symptoms ratings, non-invasive tear break-up time (NITBUT), lipid layer appearance and tear meniscus height (Keratograph 5M), horizontal fixation disparity (Saladin Near Point Balance Card with polarised lenses at 40cm) and binocular accommodative facility (primary gaze, 40cm, ±1.50D flippers). Blink rate was determined every 10 minutes using a video recording, and viewing distance was measured from a still image at the same time points. Each participant used the same smartphone and read the same text. Comprehension was tested post-task to assess compliance. Pre- and post task comparisons were made using Wilcoxon signed rank and Friedman tests; associations were examined using Spearman’s correlation.
Results :
Eye strain symptoms increased after 60 minutes of smartphone use (p=0.002), as did the numerical ratings of discomfort (p=0.01) and tiredness (p=0.02). Binocular accomodative facility decreased post-task (12 ± 4 vs 9 ± 4 cycles/min, p=0.03). Blink rate gradually increased over the task duration from 15 ± 13 to 25 ± 15 blinks/min (p=0.01). There were no significant changes in NITBUT, lipid layer, tear meniscus height or fixation disparity (p> 0.05). Mean viewing distance ranged from 30 ± 8 cm at 20 minutes to 36 ± 9 cm at 0 minutes, but these differences were not significant.
Conclusions :
Eye strain and discomfort symptoms are evident after 60 minutes of smartphone use and are accompanied by increased blink rate and reduced accommodative facility. These findings suggest that ocular symptoms during smartphone use may have a different aetiological profile to those associated with desktop computer use.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.