Video Display Viewing Time, Ocular Protection Index Associated With Abnormal Blinking

School Children
Researchers observed a significant difference in tear film stability between the normal and abnormal blinking groups.

Risk factors for abnormal blinking in both boys and girls include increased video display viewing time (VDTt) and decreased ocular protection index (OPI), according to findings published in BMC Ophthalmology.

Researchers conducted a study to explore the risk factors associated with abnormal blinking in children, and compare them between boys and girls. The study included 87 boys and 80 girls who were examined between June 2019 and June 2020. Researchers measured VDTt over the course of 6 months, recorded incomplete blinking (IC) and blinking rate, and evaluated tear film (TF) stability. Participants were allocated to groups based on their blink rate (<20 times/min = normal blinking group; >20 times/min = abnormal blinking group). 

There were no significant differences in age between the 2 groups, but there was a significant difference in TF stability (P <.05). Investigators found VDTt and OPI to be important risk factors for abnormal blinking, with cutoff values of 1.75 hours and 1.014 respectively in boys, and 1.25 hours and 1.770 respectively in girls, according to binary logistic analysis. They also noted average lipid layer thickness was an important protective factor for children using VDT for long periods, with a cutoff value of 58.5 nm in boys and 53.5 nm in girls.

The study also identified poorer meibomian gland function in boys with an abnormal blinking rate, which occurs due to the need to increase TF layer thickness to prevent further water loss. 

“Since one of the most important risk factors for abnormal blinking is the use of VDT, we infer that long-term use of VDT is also related to the function of the meibomian gland,” according to the researchers.

Study limitations include a small sample size, a relatively short observation period, and possible confounding due to air quality factors.


Zhao H, Wu SN, Zhang Q, et al. Video display terminal use and other risk factors for abnormal blinking in children: gender differences. BMC Ophthalmol. 2021;21(1):428. doi:10.1186/s12886-021-02194-w