Trigeminal-Autonomic Interaction: Evaluating Ciliary Ganglion Sensitivity and Pupillary Response in Patients with Chronic Temporomandibular Disorders (TMD)
- Apr 29
- 2 min read
Updated: May 17
https://doi.org/10.66715/ijcar/2026v2.i1.5765 | Original Research | 2026 | Volume 2 | Issue 1 | Page 57-65
Dr. Anju Sunda, Senior Resident, Oral and Maxillofacial Surgery, Prince Medical college and Hospital Sikar, Rajasthan
Abstract
Background: Temporomandibular Disorders (TMD) are increasingly recognized not just as localized musculoskeletal issues, but as complex pain syndromes involving central sensitization and dysregulation of the autonomic nervous system (ANS). The proximity of the trigeminal nuclei to autonomic centers in the brainstem suggests a functional "crosstalk." This study evaluates the Trigeminal-Autonomic Reflex by investigating whether chronic nociceptive input from the trigeminal nerve (via TMD) influences ciliary ganglion sensitivity and subsequent pupillary light reflex (PLR) dynamics.
Methodology: A cross-sectional comparative study was conducted involving 60 participants divided into two groups:
Study Group (n=30): Patients diagnosed with chronic TMD (Myofascial pain with or without limited opening) according to RDC/TMD criteria, with a pain duration >6 months.
Control Group (n=30): Age and sex-matched healthy individuals with no history of orofacial pain.
Autonomic function was assessed using Infrared Pupillometry to measure the Resting Pupil Diameter (RPD), Constriction Amplitude (CA), and Recovery Time (RT). Trigeminal sensitivity was correlated with pupillary responses by applying controlled mechanical pressure to the masseter and temporalis muscles. Ciliary ganglion sensitivity was indirectly assessed through the latency of the pupillary constriction.
Results: The study revealed significant autonomic divergence in chronic TMD patients compared to controls:
Resting Mydriasis: TMD patients exhibited a significantly larger mean RPD (5.1 \pm 0.4 mm) compared to controls (4.2 \pm 0.3 mm, p < 0.05), suggesting a baseline sympathetic bias.
Altered Pupillary Reflex: The Constriction Amplitude was significantly reduced (1.2 \pm 0.2 mm in TMD vs. 1.8 \pm 0.3 mm in controls), and the latency period was prolonged, indicating decreased parasympathetic sensitivity of the ciliary ganglion.
Nociceptive Correlation: A strong negative correlation (r = -0.68) was found between muscle pressure pain thresholds (PPT) and pupillary recovery time; patients with higher pain sensitivity showed slower pupillary redilation.
Conclusion: The findings demonstrate a clear Trigeminal-Autonomic Interaction in chronic TMD patients, characterized by impaired ciliary ganglion-mediated parasympathetic response and sympathetic hyperactivity. This "pupillary signature" suggests that chronic orofacial pain acts as a persistent autonomic stressor. Integrating pupillometric evaluation may offer a non-invasive objective biomarker for assessing the severity of autonomic involvement and central sensitization in TMD patients, potentially guiding more holistic management strategies in Oral and Maxillofacial Surgery.
Keywords: Temporomandibular Disorders, Trigeminal Nerve, Ciliary Ganglion, Pupillometry, Autonomic Nervous System, Orofacial Pain, Rajasthan.