Nystagmus is characterised by periodic involuntary movements of one or both eyes in either a fast or slow motion. Nystagmus can either be vision related or caused by a muscular imbalance. If vision related it often indicates deterioration in the central field of vision from an early age.
The involuntary eye movements can occur in circular patterns, up and down, or from side to side. This results in both eyes being unable to steadily view objects. The uncontrollable movements often result in reduced vision and depth perception and can affect balance and coordination.
There are several different forms of nystagmus which include; X-linked Infantile nystagmus, Spasmus nutans, and Acquired nystagmus.
Infantile nystagmus: Infantile nystagmus commonly develops by 2 to 3 months of age. Parents will often notice that their child’s eyes will move in a horizontal swinging movement. Infantile nystagmus is often associated with other conditions such as albinism, aniridia/congenital absence of the iris (the coloured part of the eye), underdeveloped optic nerves and congenital cataract.
Spasmus nutans: Spasmus nutans presents between 6 months and 3 years of age. The eyes may move in any direction. Parents may notice their children nod and tilt their heads to assist with steadying vision. Spasmus nutans typically improves on its own between 2 and 8 years of age.
Acquired nystagmus: Acquired nystagmus develops in later childhood or adulthood. The cause of this is often unknown but may be due to central nervous system and metabolic disorders or alcohol and drug toxicity.
Nystagmus is commonly caused by a neurological problem that is present at birth or develops in early childhood. Mutations in the FRMD7 gene causes X-linked infantile nystagmus. A condition that is considered X-linked is caused by a mutation of a gene that is located on the X-chromosome. Males, who only have one X chromosome, only require one altered copy of the gene in each cell to cause the condition. As females have two X chromosomes, despite inheriting the gene, symptoms may be less severe than affected males. Approximately half of females with an FRMD7 mutation show no symptoms of this condition. FRMD7 gene provides instructions for making a protein whose function in the human body is unknown. This protein is mostly found in the areas or the brain that control eye movement and also in the retina. Researchers suggest that FRMD7 mutations cause nystagmus by disrupting the development of certain nerve cells in the brain and the retina. Acquired nystagmus, which occurs later in life, is often a symptom of another condition or disease. Causes of nystagmus may include; lack of development of normal eye movement control in early life, albinism, very high refractive error (for example near-sightedness), congenital cataract, and central nervous system diseases.
More information on genetic inheritance patterns can be found at our Genetic Inheritance Section.
For more information, please contact the Research Department on 01 6789004 or e-mail firstname.lastname@example.org.
Nystagmus is diagnosed through a number of tests which are important for providing the correct diagnosis.
The eye doctor will ask about a person’s medical history, including any family history of eye conditions. Individuals will receive a clinical eye examination where they may be asked to read letters off a chart (Snellen chart). A refraction test may also be performed to determine the appropriate lens power needed to compensate for nearsightedness, farsightedness or astigmatism. In order to interpret a clear single image of what is being viewed the eye must effectively change focus and move and work in unison. The eye doctor will look for problems that affect the control of eye movements or make it difficult to use both eyes together.
As nystagmus is often the result of other conditions or diseases the ophthalmologist may refer you to another medical specialist (e.g. neurologist) to complete further testing to identify the cause of nystagmus and advise you on treatment options.
It’s often impossible to tell which type of retinal disease a person has just by looking into the eye. As such, a genetic test may be necessary to confirm the diagnosis of X-linked infantile nystagmus.
The Target 5000 programme provides free genetic and clinical testing to all individuals living in Ireland with an inherited retinal degeneration. Through genetic screening of the person awaiting diagnosis and their family members, the Target 5000 programme will provide more detailed information about the nature and inheritance pattern of the condition.
As gene-specific clinical trials and treatments become available, knowing the genetic mutation associated with an inherited retinal degeneration will become even more important. Taking part in this programme ensures participants are included on a national registry from which participants can be identified for clinical trials and treatments and from which further information about each of the genetic retinal degenerations can be defined. For further information on the Target 5000 programme, please contact the Research Department on 01 6789004 or email email@example.com.
There is not currently a cure for nystagmus. Eyeglasses and contact lenses do not correct nystagmus itself but they can sometimes improve vision. There are many low vision aids such as telescopic and magnifying lenses which may be of benefit, as would brigther lighting. Rarely, surgery is performed to change the position of the muscles that move the eyes. Whilst this again does not correct the nystagmus it may reduce how much a person needs to turn their head for better vision.
General eye check-ups are important for people with nystagmus, as these individuals may still be at risk of developing other kinds of eye problems that affect the general population, some of which may be treatable. If the nystagmus is caused by an underlying condition, your ophthalmologist will work closely with your primary care doctor to treat the underlying cause.
No matter what level of vision a person may have, it is important to look after the eyes. To find out more about what can be done to take care of the eyes on a daily basis, please visit our Tips for Good Eye Health.
For further information, please contact the Research Department on 01 6789004.
Great advances have been made with respect to understanding this condition, with much progress being made to develop therapies for it.
Promising research exists with an aim to develop treatments for nystagmus, with a major focus on gene therapies. These gene therapies aim to deliver a “normal” copy of the gene which is mutated in this condition into the retina. As there is a single gene (FRMD7 gene) linked to X-linked infantile nystagmus, it is a potentially good candidate for gene therapy and a number of research efforts are investigating this.
Target 5000 research, largely funded by Fighting Blindness aims to determine the genetic cause and understand the nature of the condition over time. Through Target 5000, a national registry has been developed which greatly improves access to suitable clinical trials and treatments for people living in Ireland with conditions like X-linked infantile nystagmus. For further information, please contact the Research Department on 01 6789004 or e-mail firstname.lastname@example.org.
To find out more about these studies, please contact the Research Department on 01 6789004 or e-mail email@example.com.
Information about clinical trials can be found on the Clinical trials website and can be searched by condition and trial location.
Receiving a diagnosis can be overwhelming for anyone, but this is not a journey that you have to make alone. There are many groups and resources are available to provide support for people living with Nystagmus.
Fighting Blindness offers a free and confidential counselling service (Insight Counselling). For further information please contact firstname.lastname@example.org or call 01 6746496.
A mindfulness group is also available on every Wednesday at the Fighting Blindness office at 11am.
For technology support and guidance, the Dublin-based Technology Exchange Club meets every Monday at the Fighting Blindness office at 11am. Another Technology Exchange Club, based in Cork, meet every Saturday in the Cork City Library, Grand Parade, Cork City at 11am. The Cork-based club do not meet on Bank Holiday weekends or on the second Saturday of the month. For further information please contact email@example.com or call 01 6746496.
Féach provides support for parents of children living with sight loss in Ireland.
ChildVision is the national education centre for children with sight loss in Ireland.
NCBI (National Council for the Blind in Ireland) provides support and services for people living with sight loss in Ireland.
Irish Guide Dogs for the blind helps individuals and their families to achieve improved mobility and independence.