The Effects of Chewing Gum in Preventing Eyestrain

Abstract

Purpose. To investigate the effects of chewing gum and tablet candy to reduce eyestrain in healthy individuals. Materials and Methods. A double-blinded crossover trial was conducted. Forty-six healthy individuals (23 men, 23 women) between 20 and 59 years old, feeling eyestrain, were enrolled. Each 10-year age group included 12 individuals except the 30s group, which included 10 individuals. A visual task was performed on reading material displayed on a computer screen at a fixed distance for 60 min. Gum or tablet candy of two pieces were chewed for two 15-min periods starting 15 and 45 min after starting to read. Subjects chewed gum on Day 1 and tablet candy on Day 2, and vice versa. Primary outcome is as follows: subjective eye fatigue (eye tiredness, eye heaviness, blurred vision, double vision, and eye dryness) using a visual analog scale (VAS). Secondary outcomes are as follows: subjective accommodation from near and far points of accommodation measured with a D’ACOMO, spherical equivalent refraction, and eye dryness by analyzing ring break-up time (RBUT) measured with the RT-7000 Auto Ref-Topographer. Results. The VAS scores of subjective eye fatigue were not significantly changed between chewing gum and tablet candy ( P = 0.397 - P = 0.909 ). Those scores of eye tiredness and eye heaviness were significantly longer before and after the visual task with tablet candy ( P = 0.013 and P = 0.025 , respectively) but not with chewing gum. The changes of subjective accommodation were significantly lower after the visual task between chewing gum and candy ( P = 0.043 ). There were significant differences among each age group (20 s vs. 30 s, P = 0.594 ; 20 s vs. 40 s, P = 0.002 ; 20 s vs. 50 s, P = 0.002 ). After reading, the changes of spherical equivalent refraction did not indicate a shift toward myopia ( P = 0.267 ). In the RBUT, there were no significant differences between the samples ( P = 0.680 ). Conclusions. Chewing gum helps improve the ability of the eye to focus, especially in young adults.

RETRACTED: Effects of chewing gum for tear production in healthy young subjects

“…Tears are also derived from the meibomian glands, and meibomian secretions help stabilize the tear film (Arita et al 2017). In our prior study, there were no significant differences after chewing gum in the ring break-up time values using the RT-7000 and Tear Stability Analysis System (Tomey Co., Nagoya, Japan) (Asakawa et al 2020). One of the positive aspects is that chewing gum may help activate the lacrimal glands but not the meibomian glands.…”

“…Chewing is not only a physiological action for nutrient intake through the ingestion and digestion of food, but it is also regulated by complex functions of the nerves, oral organs and tissues. The effects of chewing gum demonstrated that the maintenance of homeostasis, in the forms of blood pressure and heart rate (Kanno et al 2019), and also actions on the eye (Asakawa et al 2020), is mediated by the sympathetic and parasympathetic nerves. In the present study, we found that chewing gum may help activate the lacrimal glands by the action of the parasympathetic nerves.…”

“…Chewing is also known to act on the sympathetic and parasympathetic nerves (Kanno et al 2019). Our prior study showed that chewing gum affects the parasympathetic nerves predominantly acting to contract the iris sphincter muscle and the circular M€ uller's fibres of the ciliary muscle in healthy young subjects (Asakawa et al 2020).…”