Dynamic Visual Acuity
During assessments, we quantify a patient’s ability to maintain visual acuity and stable gaze while actively moving the head.
- The Dynamic Visual Acuity (DVA) Test
Quantifies the impact of Vestibula-Ocular Reflex (VOR) system impairment on a patient’s ability to perceive objects accurately while moving the head at a given velocity on a given axis.
- Gaze Stabilization Test (GST)
Quantifies the range of head movement velocities on a given axis over which a patient is able to maintain an acceptable level of visual acuity.
Effective image stabilization during head movement is a key factor in performing activities of daily living. This process can be severely impacted by vestibular deficits with the ability to stabilize gaze and maintain visual acuity decreasing as the severity of a vestibular deficit increases. The assessment of a patient’s ability to perform visual tasks requiring image stabilization is considered complementary to physiological tests of the VOR system.
Gaze Stabilization VOR X1 rehabilitation exercises are commonly practiced by clinicians treating patients with vestibular problems. When performing VOR X1 Rehab Training, the center target (optotype) changes direction to record visual accuracy while the head moves at the target velocity. The clinician can modify training parameters by defining the optotype size, target velocity and direction of head movement. The VOR exercises include a variety of visual targets and backgrounds, as well as the ability for the clinician to record postural sway data. During VOR rehabilitation training, the patient is required to move their head continuously for up to 2 minutes and call out the optotype direction. Accuracy of recognition is tracked as a function of head speed and direction. At the end of training, Patient Instructions can be printed for at-home exercises along with a sample size of the actual size optotype.