I hear this question from patients all the time: I’m told my dizziness and unsteadiness are coming from an inner ear problem, but I feel like there’s something wrong with my vision. My optometrist insists my eyes are fine. Is there a connection? You bet there is! The inner ear and the muscles that move your eyes are intimately connected through a reflex called the vestibulo-ocular reflex or VOR.
There are only two junctions between nerves along the path of this reflex, making it one of the fastest in the body. We can thank these reflexes to help us focus clearly when we move our head. This is referred to as gaze stability.As soon as you move your head, the vestibular apparatus in the inner ear senses the precise direction and speed of that movement and tells your brain about it. The brain then uses that information to instruct our eye muscles to counter the head movement and keep whatever you’re looking at in focus.
As I look across my kitchen at the word Panasonic on my microwave, and shake my head back and forth, nod it up and down, bounce up and down, rock side to side, etc., I’m still able to tell it says Panasonic, even if I move really quickly.
That is because my vestibular system is normal and my VOR is doing its job. If you try the same thing and your word becomes blurry and appears to shift or bounce out of focus on you, there’s a name for that. It’s called oscillopsia. For some people who have very poor inner ear function in both ears, they just cannot see clearly whenever they are in motion.
Imagine how severely limiting that would be – driving, sports, looking for items on store shelves as you walk along – forget it! This is not an eye problem that would get detected at the optometrist’s office, but instead suggests some sort of breakdown along the pathway of the VOR. Possibilities include:
One or both inner ears aren’t sensing the head movement accurately,
The nerves aren’t transmitting the message from the inner ear(s) to the brain well,
The brain isn’t processing the information properly,
The brain isn’t controlling the eye muscles well, or
There’s a problem with the eye muscles themselves
The good news is that the VOR is fairly straight-forward for an Ear, Nose, Throat (ENT) specialist, neuro-otology specialist or well-trained vestibular therapist to evaluate. Additional tests can help narrow down the location along the pathway where the breakdown is occurring.
Fortunately, the VOR is a very adaptable reflex and the brain can change the VOR’s timing or ‘gain’ in order to work around many vestibular problems. The VOR can adapt to do a better job keeping the world in focus when you move your head.
A Lifemark vestibular therapist can assess your condition and teach you gaze stabilization exercises that are proven to help. Find your closest vestibular therapist today at www.lifemarkvestibular.ca