Our balance system is comprised of three peripheral sensory systems; vestibular, vision, and proprioception. These are processed by our brain it so we feel "normal". A problem in any of these sensory systems, or in the brain (central) will result in vertigo; and / or dizziness and imbalance. Vertigo is a spinning or whirling sensation; a feeling the person or world moving when it is not. Symptoms can be present while sitting still, in specific positions, or with movement. Dizziness is more described as a lightheaded, floating, or rocking sensation, sensation of being heavily weighted or pulled in one direction, imbalance, stumbling, difficulty walking straight or when turning, clumsiness or difficulty with coordination and motion hyper-sensitivity.
Dizziness and Balance Disorders
Dizziness and balance disorders are fairly common. They can be caused by visual dysfunction, vestibular injury or disease, traumatic brain injury, stroke and sinus infection to name a few. We work with a neuro-otologist, physical therapist, vestibular therapist and vision therapist to address dizziness and balance disorders. We work in a multi-discipline dizziness and balance clinic for the evaluation and treatment of these disorders.
Dizziness and Balance Problems Related to Vision
Vision plays a significant role in maintaining good balance. Approximately 20 percent of the eye’s nerves interact with the vestibular (balance) center of the brain. There are a variety of visual dysfunctions that can cause dizziness and balance issues. Sometimes these are purely visual problems, and sometimes they are caused from other disorders such as stroke, head injury, vestibular dysfunction, deconditioning and decompensation.
VISUAL DYSFUNCTIONS CAUSING DIZZINESS AND BALANCE PROBLEMS
Aneisokonia is a condition where there is an excessive difference in prescription between the eyes, which causes a significant difference in magnification of images seen between the eyes. When this magnification difference becomes excessive, generally more than about 4%, the effect can cause disorientation, eyestrain, headache, and dizziness and balance disorders. Treatment is with contact lenses, or special magnification size matched lenses called isokonic lenses.
Normally the eyes work in perfect synchrony. However, following trauma, fever, stroke, deconditioning, or sometimes for no apparent reason, one eye will aim slightly higher than the other will. When mild and not enough to cause double vision this is called a hyperphoria. If excessive to the point of causing double vision, it is termed a hypertropia. In an effort to adjust to the vertical misalignment of the eyes, the person will frequently tip their head to mechanically help align the eyes. This in turn can cause disorders in the fluid of the inner ear and resultant dizziness and balance disorders. Treatment is with therapy to correct the muscle imbalance and prisms.
Binocular Vision Dysfunction
Binocular vision refers to how the eyes work together as a team. It is the coordination of convergence and divergence (eye teaming and alignment) with accommodation (focusing). Following trauma, fever, stroke, deconditioning, or sometimes for no apparent reason dysfunctions can occur causing the eyes to be weak or overactive. When this occurs, the eyes will manifest a tendency to drift outwards or inwards. This in turn can cause eyestrain, double vision, muscle spasm and excessive peripheral visual stimulation, which in turn can trigger dizziness and balance problems. Treatment is with lenses, prisms and therapy.
Double vision is among the most disorienting and devastating vision disorders. People suffering from double vision will often times go to great lengths to alleviate the double image because it is so bothersome. Many will actually even patch, or cover an eye, thereby eliminating the vision from one eye just to get rid of their double vision. Double vision is caused when the two eyes do not align, or work together and one eye actually turns out, in, up, or down compared to the fellow eye. The overall encompassing term for this is strabismus. The disorientation from double vision will frequently trigger dizziness and balance problems. Treatment is with lenses, prisms, therapy, partial occlusion (the “spot patch” – please see the web section on double vision), and rarely surgery.
Eye Movement Disorders
Eye movement disorders typically show up as instability of visual gaze (nystagmus), jerkiness of pursuits (eye tracking), or jerkiness of saccades (visual scanning). Eye movement disorders may be congenital, or acquired. When acquired, some of the typical causes are brain injury, stroke, vestibular dysfunction, multiple sclerosis, and other neurological disease or disorder. Sometimes, an eye movement disorder can occur for no apparent reason, termed idiopathic.
When there is an acute adult onset of nystagmus the brain does not register that it is the eyes that are shaking. Rather, the brain interprets that it is the world and objects in it that are moving. This is called oscillopsia and will frequently cause dizziness and balance problems.