The scale of the problem the researchers are confronting is considerable. Neck pain, defined as pain localized between the base of the skull and the first thoracic vertebra and laterally to the margins of the trapezius muscle, affects an estimated fifty to eighty-five percent of adults at least once in their lifetime. Roughly thirty-seven percent of those symptoms develop into chronic nonspecific neck pain, meaning pain lasting more than twelve weeks without identifiable structural pathology, and recurrent episodes often return within one to five years. In the United States, individuals with chronic nonspecific neck pain incur mean annual expenditures of 8,512 dollars, a figure 1.82-fold higher than that of the general population. Current clinical guidelines recommend exercise and patient education as first-line management, yet even when massage, strengthening, stretching, and supervised physical therapy relieve pain and disability, approximately one-quarter of patients still seek additional medical care.

The physiological rationale behind the novel intervention rests on a network most people never associate with their neck: the autonomic nervous system. Chronic musculoskeletal pain is increasingly understood to involve dysregulation between the sympathetic system, which mobilizes the body’s fight-or-flight response, and the parasympathetic system, which governs rest and recovery. After local injury, pro-inflammatory mediators excite nociceptors and trigger central reflex arcs that activate both the sympathetic system and the hypothalamic-pituitary-adrenal axis. The vagus nerve, the principal parasympathetic conduit, mediates endogenous analgesia and anti-inflammatory signaling, and recent evidence demonstrates that activating the cholinergic anti-inflammatory-analgesic pathway can attenuate pain, normalize central sensitization, and improve joint function. Conventional physical therapy can reduce pain and disability, but its effects on autonomic dysfunction are often limited, which is precisely the gap the West China Hospital team hopes to close.

Eye movement exercise enters the picture because ocular function can influence autonomic nerve function. The researchers point out that eye movement exercise, particularly smooth pursuit exercises, engages cranial nerves III, IV, and VI, with the oculomotor nerve playing a particularly prominent role. This stimulation modulates the oculomotor-vestibular-proprioceptive circuits, central pain-processing pathways, and brainstem autonomic centers, potentially enhancing parasympathetic activity while inhibiting sympathetic overactivation. The oculomotor-vestibular-proprioceptive networks are tightly coupled to brainstem autonomic nuclei, including the nucleus tractus solitarius and vagal motor nuclei, so modulation of these circuits can influence parasympathetic outflow. Chronic nonspecific neck pain is frequently accompanied by sensorimotor impairments of the head-eye-neck system, including deficits in cervical proprioception and gaze stability, and oculomotor and eye-cervical re-education programs have previously demonstrated improvements in pain, disability, and visual stability.

The trial itself is a prospective, single-centre, assessor-blinded, two-arm randomized controlled trial conducted at the Rehabilitation Medicine Center of West China Hospital, where recruitment commenced on 1 December 2025. Sixty adults aged eighteen to sixty with chronic nonspecific neck pain lasting at least twelve weeks, no nerve root symptoms, no specific cervical structural pathology, and a visual analogue scale score of at least thirty millimeters for at least five days within one week prior to enrollment are being randomly assigned in a 1:1 ratio to either conventional physical therapy alone or conventional physical therapy combined with eye movement exercise. Both groups attend supervised treatment sessions three times weekly for four consecutive weeks, twelve sessions in total, each lasting approximately sixty minutes, a deliberate design choice that equalizes therapist contact time between the arms. Exclusion criteria screen out participants with histories of cervical spine surgery, significant cervical trauma, fracture, myelopathy, or neurological disorders affecting sensory, motor, or autonomic function, as well as severe cardiopulmonary or systemic disease, pregnancy, BMI above thirty, chronic eye disease significantly influencing eyesight, and medications expected to substantially influence autonomic activity or heart rate variability.

The conventional physical therapy arm is operationally standardized across four therapeutic components. Joint mobility enhancement includes Maitland posteroanterior mobilization applied from C1 to T12 at an oscillation frequency of approximately one to two hertz, with grades I-II used when pain irritability predominates and grades III-IV when restricted mobility is the main impairment, alongside cervical extension exercises including chin tucks performed for fifteen repetitions per set across two sets. Muscle relaxation involves manual release techniques applied to the suboccipital muscles, upper trapezius, and adjacent cervical muscles, with sustained pressure or stretching maintained for thirty to forty-five seconds followed by roughly ten seconds of rest and repeated three to four times. Muscle strengthening consists of cervical isometric contractions in four directions using a standardized 11.3-kilogram elastic resistance band, fifteen repetitions with a five-second hold, plus McKenzie cervical exercise with maximal chin tucks. Cervical motor-control training uses infrared headlamp-guided repositioning exercises, in which participants maintain a projected visual target within a predefined area on a wall-mounted board positioned approximately two meters away, performed for approximately five minutes per session.

The eye movement exercise programme, embedded directly within the sixty-minute session of the intervention group, consists of three tasks. In H-shaped tracking, participants follow a therapist’s thumb through a predefined H-shaped trajectory for two complete repetitions. In spiral tracking, they follow the thumb through a spiral of three clockwise and three counterclockwise rotations per set. In near-far convergence training, the target begins approximately forty centimeters from the eyes and is progressively moved toward the participant until the maximum comfortable convergence point is reached, generally within approximately 2.5 to six centimeters from the nose, then returned to forty centimeters, with three repetitions performed. For pursuit tasks the target is positioned approximately forty centimeters from the eyes, with a visible target area of roughly 1.5 by 1.5 centimeters, and moved at a nominal angular velocity of approximately ten degrees per second while participants keep the head stabilized in a neutral position and minimize head movement. Corrective lenses are not worn during the exercise to maintain standardized visual input, and training emphasis is individualized toward tasks or directions demonstrating poorer performance, with progression permitted only when participants maintain accurate tracking, smooth continuous pursuit, a stable head position, and no clinically relevant symptoms.

The measurement battery is comprehensive and mechanistically ambitious. The primary outcome is pain intensity measured on a one-hundred-millimeter visual analogue scale, with the prespecified primary endpoint at Day 30 and the primary treatment contrast defined as the between-group difference in mean change from baseline to Day 30; a fifteen-millimeter between-group difference serves as the clinically interpretable threshold based on external chronic neck pain literature. Secondary outcomes include the Neck Disability Index, active cervical range of motion assessed in six directions with a flexible tape measure, anxiety and depression severity measured with the Zung Self-Rating Anxiety and Depression Scales, and health-related quality of life measured with the WHOQOL-BREF. Heart rate variability is prespecified as a secondary mechanistic outcome, assessed through a continuous five-minute ECG recording at a sampling frequency of 500 hertz under spontaneous breathing, with prespecified indices including SDNN, RMSSD, pNN50, LF, HF, the LF/HF ratio, and SD1 processed in R using the RHRV package. Exploratory outcomes include electrical sensory and pain thresholds assessed with a PainVision PS-2100 system and manually recorded oculomotor performance including blink frequency, successful target tracking, loss of fixation, and corrective eye movements. Data are collected at baseline, Day 15, and Day 30, with no post-treatment follow-up beyond Day 30, meaning the trial evaluates short-term efficacy rather than persistence of effects.

The statistical framework reflects contemporary methodological rigor. The primary analysis follows the intention-to-treat principle using a constrained longitudinal linear mixed-effects model estimated via restricted maximum likelihood, with post-baseline measurements as repeated dependent variables, treatment group, assessment time point, and treatment-by-time interaction as fixed effects, and baseline visual analogue scale score as a continuous covariate, while participant identity is modeled as a random intercept. This framework replaced a previously described repeated-measures ANOVA approach during manuscript preparation to better handle repeated measurements and incomplete observations, without changing the primary outcome or treatment contrast. Prespecified sensitivity analyses adjust for baseline age and Neck Disability Index score, and separately for baseline anxiety or depression scores, which are never entered simultaneously because of their potential correlation and the small sample. Missing data are handled under a missing-at-random assumption, with complete-case analysis, multiple imputation, delta-adjusted multiple imputation, and a per-protocol analysis of participants completing at least eighty percent of scheduled sessions all prespecified before database lock.

The team is candid about the trial’s limitations and what its results can and cannot show. Participant and therapist blinding is not feasible because both interventions involve active exercise, so expectation and performance bias cannot be completely excluded, although outcome assessors and statistical analysts remain blinded. The sample-size calculation was based on a standardized effect estimate derived from a pilot sample of only five participants per group, which may overestimate the true treatment effect and lower the anticipated statistical power, and the authors emphasize that findings should be interpreted with attention to the estimated treatment effect, its ninety-five percent confidence interval, and clinical relevance. Crucially, the proposed relationships among eye movement, sensorimotor integration, autonomic modulation, and pain remain exploratory: heart rate variability will be interpreted as an indirect physiological marker rather than a direct measurement of vagal activity, and associations among changes in pain, heart rate variability, and oculomotor performance will not be interpreted as evidence of causal mediation. If the trial demonstrates that integrating structured eye movement exercise into standard rehabilitation confers incremental short-term benefits over conventional therapy of equal total duration, it would inform future large-scale, long-term rehabilitation trials, potentially reshaping how clinicians think about the eyes as a gateway to pain relief.

Subject of Research: A randomized controlled trial protocol testing eye movement exercise combined with conventional physical therapy for chronic nonspecific neck pain

Article Title: Effects of eye movement exercise combined with conventional physical therapy on chronic nonspecific neck pain: a randomized controlled trial protocol

Article References: Gou, L., Yu, S., Wang, Z., Kang, Y., Hou, Y., & Yang, L. (2026). Effects of eye movement exercise combined with conventional physical therapy on chronic nonspecific neck pain: a randomized controlled trial protocol. Frontiers in Sports and Active Living, 8, Article 1929676. https://doi.org/10.3389/fspor.2026.1929676

Image Credits: AI Generated

DOI: 10.3389/fspor.2026.1929676

Keywords: chronic nonspecific neck pain, eye movement exercise, conventional physical therapy, autonomic nervous system, heart rate variability, randomized controlled trial, vagus nerve, parasympathetic activity, oculomotor training, rehabilitation, pain intensity, neck disability index