What is nystagmus?
Nothing can appear so disruptive as eyes that are constantly moving. As therapist’s, we become very concerned as we 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 in a few ways. First, is time of 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)
Another way the nystagmus may be further defined is 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 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. Further, 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”. The null point 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. In some cases, 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.
(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