Vision therapy: Occlusion, prisms, filters, and vestibular exercises for mild traumatic brain injury

A number of treatment approaches have been advocated for persistent visual complaints following mild traumatic brain injury. These include devices such as binasal occlusion, yoked prisms, vertical prisms, and filters, as well as vestibular training. We discuss the rationale and the evidence for each of these approaches. Binasal occlusion has been advocated for visual motion sensitivity, but it is not clear why this should help, and there is no good evidence for its symptomatic efficacy. Base-in prisms can help manage convergence insufficiency, but there are few data on their efficacy. Midline shift is an unproven concept, and while the yoked prisms advocated for its treatment may have some effect on egocentric neglect, their use in mild traumatic brain injury is more questionable. A wide variety of posttraumatic symptoms have been attributed to vertical heterophoria, but this is an unproven concept and there are no controlled data on the use of vertical prisms for mild traumatic brain injury symptoms. Filters could plausibly ameliorate light intolerance but studies are lacking. Better evidence is emerging for the effects of vestibular therapy, with a few randomized controlled trials that included blinded assessments and appropriate statistical analyses. Without more substantial evidence, the use of many of these techniques cannot be recommended and should be regarded as unproven and in some cases implausible.