An<unk>  —also called catford<unk> — is a rotating instrument to test vision in which individuals are seated facing the wall of the<unk> . The interior surface of the<unk>  is normally striped; thus, as the<unk>  rotates, the subject's eyes are subject to a moving visual field while the subject remains stationary, this phenomenon is called<unk>  Nystagmus. The speed of the<unk>  and the duration of the test may be varied. Control groups are placed in a<unk>  without stripes or rotation. After exposure to the rotating<unk> , subjects are surveyed to determine their susceptibility to motion sickness. A study in which the<unk>  was used to test the symptoms of the sopite syndrome showed increased mood changes in response to the visual cues, though these effects were compounded by other environmental factors such as boredom and lack of activity.
Optokinetic drum
Leonine facies
Hippocratic facies
Vitreous bulge
Spotted lunulae
Iatrosophia
Enlarged vestibular aqueduct
Grisi siknis