Pendular nystagmus is a

sinusoidal A sine wave, sinusoidal wave, or just sinusoid is a mathematical curve defined in terms of the '' sine'' trigonometric function, of which it is the graph. It is a type of continuous wave and also a smooth periodic function. It occurs often in m ...

oscillation Oscillation is the repetitive or periodic variation, typically in time, of some measure about a central value (often a point of equilibrium) or between two or more different states. Familiar examples of oscillation include a swinging pendulum ...

, which refers to the waveform of involuntary eye movements that may occur in any direction. It is characterized by the multidimensional slow eye movements of the eyes (1 Hz frequency) with an equal

velocity Velocity is the directional speed of an object in motion as an indication of its rate of change in position as observed from a particular frame of reference and as measured by a particular standard of time (e.g. northbound). Velocity is a ...

in each direction that resembles the

trajectory A trajectory or flight path is the path that an object with mass in motion follows through space as a function of time. In classical mechanics, a trajectory is defined by Hamiltonian mechanics via canonical coordinates; hence, a complete traj ...

of a

pendulum A pendulum is a weight suspended from a pivot so that it can swing freely. When a pendulum is displaced sideways from its resting, equilibrium position, it is subject to a restoring force due to gravity that will accelerate it back toward the ...

. These pattern of these movements may differ between the two eyes. Depending upon the pattern of movements, pendular nystagmus has been divided into different subtypes such as congenital nystagmus, acquired pendular nystagmus, and amaurotic nystagmus.

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Medical signs Eye diseases {{eye-disease-stub