The Influence of Temporomandibular Joint Disorders and Mandibular Position on Visual Capacities: A Case-Control Study.

Abstract

Aims: To verify the possible association between the stomatognathic and the visual system by analyzing the effects that different mandibular postures may have on the accommodative capacity and ocular convergence and by assessing whether temporomandibular disorders (TMD) can influence visual abilities.

Materials and methods: A case-control study was performed during a 1-year period on a sample of 100 subjects (50 cases and 50 controls). The subjects underwent a gnathological examination, and two visual tests were performed in three different jaw positions: maximum intercuspation, resting position, and open mouth. The statistical analyses were performed using the software SPSS program based on t-test to compare the different jaw positions and the odds ratio to understand the prevalence of visual defects in TMD patients.

Results: A statistically significant worsening was observed comparing the visual capacities measurements from the maximum intercuspation to the open mouth position; "case group" measurements showed a worsening trend compared to the "control group" (P value < 0.05 in all comparisons). Furthermore, the examinations showed statistically significant results with reference to the relationship between TMD and their negative influence on visual abilities (P value = 0.007 for convergence and P value = 0.012 for accommodation).

Conclusions: Based on our data, TMD individuals performed worse in vision tests compared to healthy subjects and the presence of occlusal contacts appears to improve convergence and accommodation. The reduced reproducibility and accuracy of the orthoptic tests and the small sample number were the principal limitations of our study. The future perspective could be to investigate whether the visual apparatus could benefit from the treatment of stomatognathic disorders.