Nystagmus

A repetitive rhythmic involuntary oscillation of the eyes that is usually conjugate. It can be thought of as an abnormality in ocular posturing and is due to a disturbance in the pathways, the organization of, or the integration of the pathways of the visual or the labyrinthine systems.

Technique for testing:

  • patient asked to follow finger at a distance to avoid convergence of the eyes
  • the finger is moved 30 degrees to each side as will loose binocular vision
  • test is done side to side, up and done, and with convergence
  • Both eyes observed.
   
   

Describing Nystagmus:

Nystagmus has a number of characteristic features which can be used to describe each occurrence as it presents itself.
 
Motion: Pendular Smooth, sinusoidal motion
Jerk Slow drift, rapid recovery
Beat Direction Horizontal Side to side
Vertical Up and down
Rotatory Rotation of Iris
Gaze Direction Horizontal Gaze left or right
Vertical Gaze Up or down
Unidirectional Nystagmus only in one direction of gaze
BiDirectional Nystagmus on both directions of gaze
Severity First Degree On one side only
Second Degree In primary position also
Third Degree On opposite side also, same beat
Conjugacy Disconjugate Jerk nystagmus in one eye, slow drift in the other.
   
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