Effects of visual input on changes in the bioelectrical activity of the cervical and masticatory muscles in myopic subjects.

The study aimed to analyze the changes within the bioelectrical activity of the cervical spine and masticatory muscles during the change of visual stimulus-open and closed eyes test. After applying the inclusion criteria, 50 subjects were included in the study, with visual impairment ranging from -0.5 to -5.75 Diopters. Four muscle pairs were analyzed: the anterior part of the temporalis muscle (TA), the superficial part of the masseter muscle (MM), the anterior belly of the digastric muscle (DA), and the middle part of the sternocleidomastoid muscle (SCM) belly during rest, teeth clenching, teeth clenching on dental cotton rollers, and active mouth opening. Statistical analysis showed a significant decrease in the bioelectrical activity during teeth clenching of all analyzed muscles during the closed eyes test. Significant decreases of electromyographic values were also observed during resting activity within TA muscles, during teeth clenching with dental cotton rollers within SCM and DA muscles, and during active mouth opening within the right masseter. Changing the visual stimulus from open eyes to closed eyes in people with myopia affects the bioelectrical activity of the masticatory and cervical spine muscles.