Smartphone gaming induces dry eye symptoms and reduces blinking in school-aged children

The ubiquitous use of smartphones among children, often exceeding recommended screen time limits, raises concerns about potential adverse health effects. While studies have linked excessive screen time to general and mental health issues and myopia progression, the impact on ocular surface health in children with healthy eyes remains understudied. Existing research in adults demonstrates that smartphone use can lead to dry eye symptoms, altered tear function, and reduced blinking. However, the short-term and long-term effects on children's ocular surface health are largely unknown. This study aimed to investigate the immediate effects of smartphone gaming on blinking, symptoms, and tear film function in school-aged children with healthy eyes, using objective and subjective measures. The researchers hypothesized that one hour of continuous smartphone gaming would lead to increased dry eye symptoms and a reduction in blink rate in children.

The literature extensively documents the increasing prevalence of smartphone ownership and usage among children globally, often surpassing recommended daily screen time limits set by organizations like the World Health Organization and national health bodies. This excessive screen time has been associated with various adverse health outcomes, including myopia progression in children and adolescents. Previous research indicates that prolonged digital device use can impact the ocular surface, leading to symptoms like eye strain, dryness, and discomfort. Studies on adults have consistently shown that smartphone viewing can negatively affect blink rate and tear film parameters. While some research has examined the ocular surface effects of smartphone use in children already diagnosed with dry eye, a prospective study on children with healthy eyes investigating the impact of smartphone use on blinking was lacking before this study.

This prospective interventional study recruited 36 children (14 male, 22 female) aged 6–15 years with normal vision and no pre-existing ocular conditions. Participants played two smartphone games (Despicable Me: Minion Rush and Racing Penguin) for one hour. Ocular symptoms were assessed using three questionnaires: SANDE (Symptom Assessment in Dry Eye), JOSS (Instant Ocular Symptoms Survey), and NRS (Numerical Rating Scale). Tear film parameters (lipid layer thickness, tear meniscus height, non-invasive tear break-up time) were measured using LipiView interferometer and Oculus Keratograph 5. Blink rate and interblink interval were continuously monitored using a wearable eye-tracking headset before (during conversation) and throughout the gaming session. Paired t-tests were used to compare symptom and tear film changes before and after gaming, while repeated measures ANOVA with Bonferroni correction analyzed changes in blinking during the hour. Pearson bivariate correlation examined associations between changes in blink parameters, symptoms, and tear film function.

After one hour of smartphone gaming, children experienced significant worsening of dry eye symptoms. SANDE scores increased by 8.2 units (p=0.01), JOSS scores by 1.3 units (p<0.001), and average NRS scores by 6.3 units (p=0.03). NRS scores for comfort and tiredness also increased significantly. Notably, tear film parameters (lipid layer thickness, tear meniscus height, non-invasive tear break-up time) did not show significant changes. Blink rate dramatically decreased from 20.8 blinks/min to 8.9 blinks/min (p<0.001) within the first minute of gaming and remained significantly lower throughout the hour. The interblink interval increased from 2.9 s to 8.7 s (p=0.002) in the first minute and remained elevated. Importantly, no significant association was found between changes in blink parameters and symptom worsening.

This study provides the first evidence of the rapid and sustained impact of smartphone gaming on blink rate and dry eye symptoms in healthy children. The significant reduction in blink rate and the substantial increase in interblink intervals suggest a direct effect of smartphone use on blinking behavior. While tear film parameters remained stable in the short term, the increased symptoms indicate that the reduced blink rate is not adequately compensated for, leading to discomfort and dryness. This aligns with findings from adult studies, suggesting that the mechanism underlying these effects may be similar across age groups. The lack of correlation between symptom changes and blink parameters could be due to the short duration of the intervention, or that other factors beyond blink rate may contribute to symptom development in children.

This study demonstrates that even a single hour of smartphone gaming can induce significant dry eye symptoms and a substantial reduction in blink rate in children with healthy eyes. Given the widespread and often excessive use of smartphones among children, these findings underscore the need for further research to investigate the long-term effects of prolonged smartphone use and to develop recommendations for safe and healthy screen time practices. Future research should focus on longer-term studies examining the cumulative impact of smartphone use on ocular surface health and the development of potential interventions to mitigate these effects. The study also highlights the value of blink rate as a useful indicator of ocular surface changes in children.

This study's primary limitation is its short-term nature (one-hour intervention). Longer-term studies are needed to assess the cumulative effects of smartphone use on the ocular surface. The lack of a control group not exposed to smartphone use also limits the ability to completely rule out other factors influencing the observed changes. Additionally, the specific games used could influence the results, and future studies could explore variations in gameplay and screen characteristics.