The Axial Length of the Eyeball and Bioelectrical Activity of Masticatory and Neck Muscles: A Preliminary Report

Abstract

Objective. The present study aimed to evaluate the correlation of eye length and bioelectric activity of temporalis, masseter, digastric, and sternocleidomastoid muscles in women with myopia compared to healthy women. Methods. Based on the exclusion and inclusion criteria, 42 women aged 24 years (±2 years) were eligible for the study. Two equally sized groups with myopic (n = 21) and emmetropic healthy subjects (n = 21) were formed. An electromyographic study of the examined muscles was performed in four conditions: at rest, during maximal voluntary clenching in the intercuspal position, during maximal voluntary clenching on dental cotton rollers, and during maximal mouth opening using BioEMG III (BioResearch Associates, Inc. Milwaukee, WI, USA). The IOL Master 500 (Carl Zeiss Meditec, Jena, Germany) was used to examine the eyeball length. Statistical analysis showed significant positive correlations during mouth opening in both groups with open and closed eyes. Results. A greater number of correlations between the analyzed variables was observed in emmetropic women. In almost all cases, the longer axial eye length was associated with an increase in the bioelectrical activity of the analyzed muscles. Significant correlations were most often observed within the masseter and digastric muscles during the maximum mouth opening and at rest. Conclusion. There is a relationship between the bioelectrical activity of the masticatory muscles and the axial length of the eyeball on the same side.

The Influence of Visual Input on Electromyographic Activity and Patterns of Masticatory and Cervical Spine Muscles in Emmetropic Caucasian Subjects by Gender

“…Connections between the musculo-fascial system and the sight organ are also observed in people without a refractive error. A correlation has been observed between the axial length of the eyeball, bioelectrical activity [8], and the thickness of selected muscles of the masticatory organ [7]. Such connections have also been found between retinal thickness and intraocular pressure in subjects without any defect and the activity as well as thickness of the muscles [7].…”

“…The above papers also do not differentiate subjects by gender, which can be an important factor [15]. Additionally, they do not analyze whether subjects had measured intraocular pressure or eyeball length (the aforementioned variables are associated with changes in surface electromyography (sEMG) signal [7,8]). What is more, the abovementioned studies do not indicate the subjects' race.…”

Myopia Is Suppressed by Digested Lactoferrin or Holo-Lactoferrin Administration

“…Oral native-LF has been shown to be effective in downregulating MMP-2 expression in the sclera to suppress the progression of myopia [ 26 ]. The visual system, including the extraocular muscles, plays a critical role in both moving the eyes and stabilizing resulting images [ 12 , 13 ]. Recent studies suggest that myopia may be associated with masticatory muscle bioelectrical activity and muscle thickness.…”

“…Owing to morphological changes, physical stimuli such as stress are applied to the posterior segment of the eye, resulting in visual impairment, such as myopic macular degeneration (MMD), retinal detachment (RD), cataract, and open angle glaucoma (OAG), and macular optic neuropathy [ 3 , 10 , 11 ]. The visual system comprises the extraocular muscles, which play a vital role in both moving the eyes and stabilizing the resulting images [ 12 , 13 ]. Myopia has also been proven to be associated with masticatory muscle bioelectrical activity and muscle thickness.…”

The Incidence and Severity of Myopia in the Population of Medical Students and Its Dependence on Various Demographic Factors and Vision Hygiene Habits

“…The state in which the eyeball’s length is increased is called axial myopia. The elongation is often accompanied by bioelectrical activity [ 9 ] and the thickening of cranial and cervical spine muscles [ 10 ]. The multifactorial etiology of myopia depends on genetic and lifestyle factors.…”