Optokinetic Drum, Black and White Stripes. Drum height: 25 cm
Optokinetic Nystagmus (OKN) may be used as an objective measurement of vision in an otherwise non-responsive or malingering patient. It is useful in pediatric cases to determine the presence or absence of vision.
A positive nystagmus response consists of a slow movement of the eye while following the objects on the rotating drum, followed by a rapid recovery phase in the opposite direction.