Relationship of the Lateral Rectus Muscle, the Supraorbital Nerve, and Binocular Coordination with Episodic Tension-Type Headaches Frequently Associated with Visual Effort.

Objective: To study the relationship between tension-type headaches and the oculomotor system in terms of binocular coordination, mechanosensitivity of the supraorbital nerve, and myofascial trigger points in the lateral rectus muscle, assessing the influence of visual effort caused by using a computer at work.

Design: Observational study with blind evaluation of the response variable.

Methods: Two groups were compared: 19 subjects with tension-type headaches and 16 healthy subjects, both exposed to computer use at work. A blinded assessor conducted three tests: measurement of the supraorbital nerve pressure pain threshold using a pressure algometer, evaluation of myofascial trigger points of the lateral rectus using the verbal numerical scale, and assessment of binocular coordination in smooth pursuit eye movements using an innovative video-oculography system. Tests were performed before work began and four hours later, and subjects in the headache group were examined when they presented a headache score of less than or equal to 3 on the verbal numerical scale.

Results: The headache group presented a greater sensitivity of the supraorbital nerve and greater local and referred pain of the lateral rectus ( P  < 0.05). Visual effort caused a significant worsening of these variables in both groups. However, binocular coordination after visual effort was only significantly affected in the headache group ( P  < 0.05), primarily in horizontal movements.

Conclusions: The finding of a higher alteration of the sensitivity of the supraorbital nerve, the myofascial trigger points of the lateral rectus, binocular coordination, and the significant influence of visual effort in patients with tension-type headaches suggest a new clinical perspective for problems related to tension-type headaches.