| conjugate nystagmus | A nystagmus in which the two eyes move simultaneously in the same direction. (05 Mar 2000) |
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| convergence-retraction nystagmus | Irregular, jerky nystagmus combining convergence and retraction of the eye into the orbit, especially on attempting an upward gaze. Synonym: Koerber-Salus-Elschnig syndrome. (05 Mar 2000) |
| positional nystagmus | Nystagmus occurring only when the head is in a particular position. (05 Mar 2000) |
| seesaw nystagmus | A nystagmus in which one eye moves upward as the other moves downward, often combined with a torsional rotation (down and out, up and in-as in a see-saw). (05 Mar 2000) |
| nystagmus | <neurology> An involuntary, rapid, rhythmic movement of the eyeball, which may be horizontal, vertical, rotatory or mixed, i.e., of two varieties. Origin: Gr. Nystagmos = drowsiness, from nystazein = to nod (18 Nov 1997) |
| nystagmus, optokinetic | The normal or physiological nystagmus induced by the attempt to fixate objects moving rapidly across the field of vision. It occurs, for example, when viewing objects from a moving railroad car or automobile. It is also called railroad nystagmus. (12 Dec 1998) |
| nystagmus, physiologic | Involuntary rhythmical movements of the eyes in the normal person. These can be naturally occurring as in end-position (end-point, end-stage, or deviational) nystagmus or induced by the optokinetic drum (nystagmus, optokinetic), caloric test, or a rotating chair. (12 Dec 1998) |
| nystagmus test | A test for vestibular function, made by irrigating the external auditory meatus with either hot or cold water; this normally causes stimulation of the vestibular apparatus, resulting in nystagmus and past-pointing; in vestibular disease, the response may be reduced or absent. Synonym: caloric test, nystagmus test. (05 Mar 2000) |
| deviational nystagmus | A jerky, physiologic nystagmus occurring in a normal individual when attempts are made to fixate a point at the limits of the field of fixation. Synonym: deviational nystagmus. (05 Mar 2000) |
| dissociated nystagmus | A nystagmus in which the movements of the two eyes are dissimilar in direction, amplitude, and periodicity. Synonym: dysjunctive nystagmus, incongruent nystagmus, irregular nystagmus. (05 Mar 2000) |
| downbeat nystagmus | A vertical nystagmus with a rapid component downward, occurring in lesions of the lower part of the brainstem or cerebellum. (05 Mar 2000) |
| dysjunctive nystagmus | A nystagmus in which the movements of the two eyes are dissimilar in direction, amplitude, and periodicity. Synonym: dysjunctive nystagmus, incongruent nystagmus, irregular nystagmus. (05 Mar 2000) |
| incongruent nystagmus | A nystagmus in which the movements of the two eyes are dissimilar in direction, amplitude, and periodicity. Synonym: dysjunctive nystagmus, incongruent nystagmus, irregular nystagmus. (05 Mar 2000) |
| irregular nystagmus | A nystagmus in which the movements of the two eyes are dissimilar in direction, amplitude, and periodicity. Synonym: dysjunctive nystagmus, incongruent nystagmus, irregular nystagmus. (05 Mar 2000) |
| ocular nystagmus | The pendular or, rarely, jerky nystagmus seen in severely reduced vision. Synonym: amaurotic nystagmus. (05 Mar 2000) |