High level whole-body vibration training induces isometric muscle exercise in many muscles throughout the body, especially when in the standing position. Potential benefits include use in physical therapy and sports training, and such exercise is generally thought to increase bone and muscle health [3]. One case study described a reduction in diabetic peripheral neuropathic pain with use of whole-body vibration therapy [4].
Vibration and shaking have been shown to have effects on various tissues in the human body [3]. Vibration can be caused by situations such as occupational environment (e.g. pneumatic drill operation), trauma (e.g. shaken baby syndrome), and whole-body vibration training exercise. Some documented findings of adverse vibration after-effects include vasospastic diseases in hands [5] as well as ocular effects such as increased pigment within the trabecular meshwork, vitreous liquefaction [6] and retinal and vitreous bleeding in child abuse [7]. Other harmful ocular effects from vibratory sources include sling-shot forces and bungee cord jumping, which may produce an exaggerated vitreo-retinal traction effect.
Our patient had utilized a whole-body vibration training device for 60 s three times a few hours before the onset of his ocular symptoms. He reported that his head shook and teeth chattered during the exercise and that the forces to his body were quite severe. He was in a standing position holding the handlebars with his knees straight. The device used by our patient included a footplate on which the user can position him or herself that vibrates at a frequency up to 25–50 Hz. One study details how mechanical resonant frequency can affect the eye, outlining different vibration frequencies between 5 to 50 Hz with secondary transmission frequency to the eye [8]. This study suggests the approximate resonant frequency of the eye to be 18 Hz and a partial resonance of 10–12 Hz for the vitreous body [8].
In the case of our patient, it is hypothesized that one possible pathogenesis of the retinal tear and vitreous hemorrhage was instigated by the vibrations from the training machine transmitting a vibratory force to the eye and vitreous. In various types of vitreous-induced retinal tear formation, it is thought that vitreous movement causes shear injury to the retina at the vitreous base. The tear in our patient occurred at the vitreous base. The vibratory force probably caused his retinal tear and vitreous hemorrhage since the onset of symptoms was within 24 h of using the whole-body vibration training device. We believe our patient and those in the Bertschinger and Gillan papers strongly suggest that high-force vibration training may cause retinal tears in susceptible persons. A vitreous hemorrhage without retinal tears was reported in a 43-year-old high-myope by Bertschinger; this occurred within 2 weeks after beginning twenty-minute sessions twice per week. Gillan reported a case of a 52-year-old man who had previously used whole-body vibration training without symptoms but after a single 20-min session of training he developed a new floater within 2 min of completion and a significant drop in vision within 5 min. Though our patient is the third documented case of vitreous hemorrhage following whole-body vibration training, he is the first to show probable causation of a retinal tear and vitreous hemorrhage with whole-body vibration training.
