The Functional Effects of Nystagmus

What is nystagmus?

Nothing can appear so disruptive as eyes that are constantly moving. Therapist’s become very concerned as they attempt to imagine how a child with nystagmus sees the universe and the functional affects of these constantly moving eyes.

Nystagmus is an involuntary movement of the eyes. While most are in a horizontal plane, the nystagmus may be vertical, or even rotary.

The nystagmus may be defined by the time of onset.

  • A congenital nystagmus is present at birth or develops in the first six months after birth.
  • An acquired nystagmus develops later in life and may be assist with multiple sclerosis, brain injury or drug and alcohol use. (1)

The nystagmus may be further defined by the type of movement observed.

  • A “jerk” nystagmus is slow in one direct and fast in the other
  • A “pendular” nystagmus is the same speed in both directions
  • A “rotary nystagmus” has the rotating on the Z-Axis

The cause of most congenital nystagmus is may be associated with:

  • retinal disorders leading to low vision
  • Albinism
    • Albinism has several vision related co-morbidities including low vision and retinal problems, which may be present as well(2)
  • a family history of nystagmus
  • neurological problems at birth

These conditions may lead to life long nystagmus causing social as well as low vision related problems (3)

There are not many effective treatments for nystagmus with medications (gabapentin and memantine) emerging as helpful in some cases. (6)

Here are some videos with examples of nystagmus

Adaptation to nystagmus

Children with congenital nystagmus do not see the world moving constantly. The brain develops with this occurring and adapts though the child may need glasses to get their best vision. There is evidence that congenital nystagmus has little effect on reading performance(4), while another study suggest “crowding” could be a problem decreasing reading performance(5).

The initial adaption to an acquired nystagmus is location of the “null point”. This is a head position in which the nystagmus is reduced or eliminated. This may be perceived in child as a torticollis making an eye exam critical in children with torticollis. Surgical intervention may be used to realign the eyes to “move” the null point to allow for a better head position.

What do we do to help?

There is no effective therapeutic treatment a PT or OT can do to reduce a nystagmus. The child should be in best corrected visual acuity to use his vision most effectively. Know that the child with congenital nystagmus does not perceive the world as bouncing around. It becomes the job of therapist to make sure those usual developmental skills are learned or adaptations made for low vision as needed.

Learn More

Learn more about this subject in a live course and webinar presented by Robert.  Its now available as a webinar too!! Hosted by PESI Education.

 

(1) Does your child have involuntary eye movements (nystagmus)? (n.d.). Retrieved from https://www.allaboutvision.com/conditions/nystagmus.htm

(2)Summers, C. G. (2009, June). Albinism: Classification, clinical characteristics, and recent findings. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/19390472

(3)Pilling, R. F., Thompson, J. R., & Gottlob, I. (2005, October). Social and visual function in nystagmus. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/16170116

(4)Barot, N., McLean, R. J., Gottlob, I., & Proudlock, F. A. (2013, June). Reading performance in infantile nystagmus. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/23462273

(5)Huurneman, B., Boonstra, F. N., & Goossens, J. (2016, August 01). Perceptual Learning in Children With Infantile Nystagmus: Effects on Reading Performance. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/27548897

(6)Papageorgiou, E., McLean, R. J., & Gottlob, I. (2014, October). Nystagmus in childhood. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/25086850

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“Can eye movement problems be related to torticollis?”

Ocular Torticollis

Torticollis can be caused by several things. Delays or problems in the integral development of muscle tone, the vestibular system and propreioception can all be causes.  Eye alignment, nystagmus and acuity problems can also affect head position.  When vision is the primary cause for torticollis, it is referred to as ocular torticollis.  One study found 20% of torticollis related to ocular problems. (1)

Eye alignment

Head tilts and head turns are common signs of eye alignment problems. Deviations between eyes in the horizontal plane (hyper- or hypo- tropia) can cause head tilts in the brains attempt to see a single, fused image. Head turns (rotation) to right or left can be caused by strabismus (eso- or exo- tropia). Again, the brain turns the head in attempt to not see double. Other more complex movement patterns can also cause head position and posture problems.

Nystagmus

Nystagmus is an involuntary movement of the eyes. This is generally associated with a neurological problem. They can be congenital or acquired. Many times, patients with a nystagmus will turn their head to find the point at which the nystagmus stops. This point, called the “null point” allows for improved vision for the patient.

Acuity problems

Astigmatism, a condition in which the eyeball is not perfecting round but more football shaped, can also cause visual acuity problems that might facilitate a head tilt in order to improve vision.

Eye Exam

Every child should have their first eye exam at 6 months (per AOA recommendations). A through eye exam that includes a binocular vision exam would find eye alignment problems most likely to cause ocular torticollis.  If treating a patient with torticollis of unknown cause, a binocular vision exam could be helpful in identify the problem. Frequently, prisms and lens can be prescribed that can help reduce the torticollis.

Learn More

Learn more about this subject in a live course and webinar presented by Robert.   Hosted by PESI Education

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Assessing Eye Movements

Assessing Eye Movements

Assessing eye movements should be a regular part of every therapists evaluation process. We get 75% of the information about our environment from vision and vision affects things like reading, handwriting and balance.

Before starting this evaluation, ask about the patients most recent eye exam. A patient not in best corrected visual acuity may have difficult time fixating and therefore show poor ocular motor skills. Every child needs a compete

Nystagmus

An involuntary movement of the eyes, called a nystagmus.  These are described as a congenital or acquired nystagmus and further described as jerky (faster in one direction than the other) or pendular (same speed in each direction).

Congenital Nystagmus

Assessing Eye Movements

Assessing eye movements is quick and easy and gives the therapist vital information on about the patient may be seeing the world . Its easy to do…just watch!!!

 

 

Learn More

Learn more about this subject in a live course and webinar presented by Robert. Hosted by PESI Education

About the Author