An oculomotor test is essential to detect a central impairment of the oculomotor system and/or vestibular ocular system. In practice, the patient is provided with videonystagmography goggles containing an infrared camera that measures eye movements in the dark. The patient must follow the instructions listed below depending on the system being tested.
Patients must gaze at a target in front of them rapidly moving horizontally from left to right and from right to left, sometimes randomly. The same test is then done vertically.
Patients must follow a target moving slowly at different frequencies, 20 Hz or 30 Hz, from left to right, horizontally and vertically.
Bright spots move from left to right or from right to left and the patient must look straight ahead. The movement of the bright spots produces the optokinetic reflex. In central pathologies such as stroke, the patient’s optokinetic reflex gain is reduced.
It is therefore very important to perform these tests before the VNG assessment for vertigo.