Effect of osteopathic vs sham treatment and test-retest improvements on smooth pursuit eye movements

OBJECTIVE: While positive impacts of osteopathic manipulative treatment (OMT) on the human visual system have long been proposed, even in individuals without visual or oculomotor symptoms, scientific evidence supporting this hypothesis remains insufficient. This randomized, three-arm parallel clinical trial aimed to compare the effects of OMT vs. sham OMT and test-retest improvements on ocular pursuit. METHODS: 145 participants aged 18-35 years were randomly assigned to one of three groups: an experimental OMT group (n = 53), a sham OMT group (n = 51), or a no-treatment control group that received no manual contact (n = 54). The experimental intervention consisted of a single OMT session delivered by an osteopathic practitioner. The proportion and latency of smooth pursuit eye movements (slow, continuous eye movements that follow a visual target) were assessed before and after the intervention. RESULTS: Overall, the mean proportion of smooth pursuit eye movements increased slightly but significantly in both the experimental OMT group (by 0.78%; 95% CI, 0.24-1.33) and the control group (by 1.2%; 95% CI, 0.64-1.75). Pursuit latencies decreased by 12 ms (95% CI, 1.2-22.9) and 24.1 ms (95% CI, 13.6-34.5), in these same groups, respectively. Importantly, there was no evidence of between-group differences for either outcome (P = .12 and P = .11). CONCLUSION: The observed enhancements in ocular pursuit quality may be attributable to test-retest benefits. Further clinical trials involving older participants or patients with oculomotor impairments should be conducted to clarify potential clinical implications.