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Volume 1 - Dealing with Nystagmus
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Lecture 14 of 24 NEXT»
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The Nystagmus Patient in Clinical Practice
1. Nystagmus - Definition: An involuntary rhythmic to and fro movement of the eyes.
 Jerk Nystagmus - Accelerating slow phase - rapid refixation - usually considered motor induced.
2. Congenital Motor Jerk Nystagmus usually occurs with normal eyes but abnormal (presumably) brain stem behavior. Movement of the eyes reduces the time the object of regard is on the fovea thereby reducing vision. The etiology of congenital motor nystagmus is not known.
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With the eyes moving back and forth the object of regard does not remain on the fovea - vision is reduced - in cases of congenital nystagmus the patient does not perceive movement of the object of regard. |
In cases of congenital motor nystagmus if the eyes can be made still, vision can be normal or near normal. This is called achieving the null.
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This can occur with face turn or even elevation or depression to find the null |
Or with convergence | |  Pendular Nystagmus - The eyes move with equal speed in both directions but with variable amplitude. Usually caused by poor vision occurring early in life
In Sensory Nystagmus, a teliologic explanation is that the movement of the eyes spreads the object of regard over a larger retinal area to obtain more information, resulting in more efficient vision.
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Some types of patients who may have pendular nystagmus from poor vision -
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Universal Albinism
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Ocular Albinism
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Congenital Cataract
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Optic Atrophy/Hypoplasia
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Etc. |
2-4-6 "Rule" for Sensory (Pendular) Nystagmus
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Before 2 years*
Before 4 years
After 6 years
* This nystagmus is not present at birth but develops by approximately 6 months. |
Nystagmus
"Always"
Often
"Never" |
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In clinical practice, Pendular and Jerk components can and usually do coexist - these movements may also be combined with a rotary component to the nystagmus in some cases especially nystagmus with congenital esotropia.
Manifest Latent Nystagmus (an oxymoronic term) occurs in about one half of congenital esotropia patients.
Nystagmus present with both eyes uncovered - vision required.
 Decelerating slow phase
Manifest latent nystagmus is presumably caused by an inborn error in the binocular system. Since the deviated, or the suppressed eye, is not fully participating in the visual act - the nystagmus could be occurring because one eye is not working properly and is acting like it were occluded - the more understandable form of latent nystagmus is that which occurs when one eye is covered - it is truly latent nystagmus.
School children with latent nystagmus will usually fail school vision screening when one eye is covered. These children should be allowed to have vision checks with both eyes open seeing that they are uncovered. A note for the parents to give to the teacher is useful.
Spasmus Nutans An idiopathic nystagmus of early childhood -- self-limiting and benign.
The Spasmus Nutans Triad
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1 Nystagmus in one eye or nystagmus unequal between the eyes. |
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2 Torticollis |
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3 Head Nodding | |
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The onset of spasmus nutans is about 6 months - it usually goes away before 3 years. | True spasmus nutans is benign and self-limiting but it may be indistinguishable from acquired central nervous system nystagmus of childhood from a serious cause and for this reason most ophthalmologists obtain imaging of the head with MRI or CT with spasmus nutans. Note: a spasmus-nutans-like picture with neurologic cause is not spasmus nutans which by definition is idiopathic.
Patients with 1) Congenital Motor Nystagmus, 2) Sensory Pendular Nystagmus, and 3) Manifest Latent and Latent Nystagmus are usually apparent from early life and/or are associated with an obvious ocular abnormality, 4) Spasmus Nutans falls a little away from the picture in that it is acquired, but is by definition benign nystagmus.
 In contrast to the types of nystagmus noted above, which have visual but not life threatening implications, the "red flag" of nystagmus is that which is acquired, vertical and/or with retraction or flutter or has "chaotic" eye movements (often called nystagmoid movements) and can be associated with CNS lesions. These types of nystagmus require work up - starting with imaging. They are usually outside the scope of clinical ophthalmology for definitive treatment.
More about nystagmus later.
The Strabismus Minute, Vol.1, No. 20 Copyright (C) 1999 Eugene M. Helveston All Rights Reserved
Editor-in-Chief: Eugene M. Helveston, M.D.
Associate Editor: Faruk H. Orge, M.D.
Editorial Board: Bradley C. Black, M.D.
Edward O'Malley, M.D.
David A. Plager, M.D.
Derek T. Sprunger, M.D.
Daniel E. Neely, M.D.
Naval Sondhi, M.D.
Senior Editorial Consultant: Gunter K. von Noorden, M.D.
Graphics: Michelle L. Harmon
Technical Support: George J. Sheplock, M.D.
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