What is Nystagmus?
Nystagmus is an abnormality of eye movements where the eyes shake spontaneously.
What causes Nystagmus?
Nystagmus is caused by either poor vision or central nerve system abnormalities. Nystagmus in children is mostly due to visual system maldevelopment (e.g. a poorly developed fovea – the structure in the retina that gives us “reading” vision), retinal dystrophy or optic nerve hypoplasia.
What are the symptoms of Nystagmus?
Poor vision, photophobia, jiggling/shaking of the eyes or strabismus. Children can can present with an abnormal head turn to maximize their vision by utilising the “null zone” (this is the eye position where the nystagmus is at its least).
Is nystagmus inherited?
Nystagmus itself is not inherited however if it is associated with a retinal dystrophy then it is inherited as part of the this.
How is nystagmus treated?
Treatment is limited for nystagmus apart from treating underlying conditions such as congenital cataract. Nystagmus tends to improve with age and this is often associated with an improvement of vision. Children with nystagmus often have refractive errors causing focus issues and these can be effectively treated with glasses. Surgery to correct an abnormal head posture is effective in people with nystagmus, this not only corrects the abnormal head turn but it can also improve their vision.
Behaviours and Conditions that might indicate Nystagmus
- Obvious involuntary eye movement when either actively looking and/or when not.
- Despite the eye movement, most children see a stable image.
- Head tilt or turn as a way to still some of the movement (null point), though not all children may adopt this strategy.
- Difficulty focusing on finer detail for lengths of time, particularly when younger and when learning strategies to manage their nystagmus.
- Coming in close to material for better viewing.
- The eye movement may worsen when the child is tired, stressed or hungry.
- The child may experience depth and distance issues, which means they may have difficulty with mobility, appear uncoordinated and find ball sports challenging.
- The child may be hesitant when going down stairs or kerbs or from one level to another. When younger, they may use their feet to help determine changes in depth from one surface to another.
- Switching focus repeatedly can be challenging such as copying from the board to an exercise book.
What to do
- A Functional Vision Assessment will review the infant, child or young person’s use of vision. This will include observations and assessments of how he/she uses vision in real life situations and for learning and access to Te Whāriki, the New Zealand Curriculum, the Blind and Low Vision Education Network, NZ (BLENNZ) Curriculum and the Expanded Core Curriculum.
- Adaptations or modifications to the environment and materials used may be beneficial for assisting visual access. An environmental audit may be helpful to reduce risks of accidents in corridors, on stairs or in various settings where judging depth and distance is required.
- Strategies and suggestions for low and high tech devices later in life to assist the learner’s functional vision are also included in the functional vision assessment. Some of these strategies can include a review of print size, contrast levels and the effects of clutter. Magnifiers and dark-lined paper may be helpful. Handheld technology devices or BYOD’s (bring your own device) can avoid difficulties seeing the board and switching focus.
- The child may need more time to see what they are looking at which then leads to their response times being slower.
- A systematic search and scan can be introduced and practiced when viewing material and within various environments.
- Monitor fatigue, hunger and emotional states that can intensify the nystagmus. Take vision breaks, if and when, needed.