Dynamic Visual Acuity (DVA) describes visual image stability where the vestibular ocular reflex (VOR) counters head motion by moving the eyes in the opposite direction to maintain a clear view of the world. The eDVAUSB provides static and dynamic visus information in normal subjects such as pilots and athletes and in patients with vestibular or neurological disorders.
Simpler versions of this test involve reading an eye chart while the patient is shaking their head. If the patient must move up two lines on the eye chart to see the characters clearly, then their VOR is considered abnormal.
One problem with the simple test is that the character can be read while the patient’s head is stopped. The eDVAUSB computerized version will only present the character to the patient when their head is moving at a high velocity where only the VOR is functional and not pursuit. The test is also direction sensitive, so all the six semicircular canals can be tested separately.