Nystagmus (Dancing Eyes) : Types, Symptoms, Causes, Treatment & Prevention.

NYSTAGMUS :

WHAT IS NYSTAGMUS?

Nystagmus, also known as ‘Dancing Eyes’ is a condition of involuntary and quick, eye movements acquired in infancy or later. The eyes move & down, side to side, or even in a circle and the person suffering, can't control this. This may result in reduced vision and other vision problems.

DIFFERENT FORMS OF NYSTAGMUS ALONG WITH

THEIR CAUSES :

• Early-Onset Nystagmus: Early-onset nystagmus is usually mild and non-progressive. It can be so mild that generally, the affected person is unaware of its spontaneous eye movements. But still, vision can be impaired depending on the severity of the eye movements. Mutations of the gene FRMD7 located on the X-chromosome cause X-linked infantile nystagmus. This occurs more frequently than acquired nystagmus. Infantile nystagmus also comes under this. Infantile nystagmus often develops by 2 - 3 months of age. The eyes tend to move in horizontal swinging fashion. This can be caused by :

i.         Albinism : ( To know more about albinism you may have a look on our this article ALBINISM).

ii.       Underdeveloped optic nerves.

iii.      Congenital cataract.

iv.     Aniridia.

v.       Rod monochromatism.

vi.     Persistent tunica vasculosa lentis,etc.

•     Acquired nystagmus: This develops in later childhood or in adulthood, sometimes also known as idiopathic nystagmus because the cause behind this is unknown or idiopathic. Some common causes which may be responsible for this are :

1. Diseases & disorders of the central nervous system (CNS) like :

a)      Multiple sclerosis

b)      Brain abscess (Cerebellar)

c)       Thalamic haemorraghe

d)      Cerebellar ataxia

e)      Chiari Malformation

f)       Stroke

g)      Trauma

h)      Tumor

2. Metabolic disorders and alcohol and drug toxicity:

a)      Alcohol intoxication

b)      Barbiturates

c)       Ketamine

d)      Lithium

e)      MDMA

f)       Phencyclidine (PCP)

g)      Phenytoin (Dilantin)

h)      Salicylates

i)        Amphetamines

j)        Nitrous Oxide

k)      Benzodiazepines

l)        Pregabalin

m)    Thiamine deficiency or Beri-Beri disease

•     Spasmus Nutans: This usually occurs between 6 months and 3 years of age and will improve on its own between 2 and 8 years. Children with spasmus nutans form of nystagmus often nod and tilt their heads. Their eyes might move in any direction. This form of nystagmus does not require treatment in most cases.

Some Other Common Types Of Nystagmus Observed:

•  Optokinetic nystagmus: A nystagmus induced when looking at a moving visual stimulus such as moving horizontal or vertical lines or stripes.

• Postrotatory nystagmus: We can understand this with the help of an example : If a person spins itself continuously and stops suddenly, the fast phase of nystagmus will be the opposite direction of rotation, known as the "post-rotatory nystagmus", while the slow phase will be in the direction of rotation.

• Positional nystagmus: This occurs when a patient’s head is in a specific position.

• Spontaneous nystagmus: This occurs randomly, regardless of the position of the person’s head.

CAUSES :

Some other general diseases and conditions that causes and may be common to all types of nystagmus are:

• Aniridia
• Brain tumors (medulloblastoma, astrocytoma, or other tumors in the posterior fossa)
• Canavan disease
• Head trauma
• Lateral medullary syndrome
• Ménière's disease and other balance disorders
• Multiple sclerosis
• Optic nerve hypoplasia
• Pelizaeus–Merzbacher disease
• Superior canal dehiscence syndrome
• Tullio phenomenon
• Whipple's disease
• COVID -19 : Surprisingly but yes, even COVID-19 can also cause nystagmus.
• Exposure to strong magnetic fields (for e.g. in MRI machines)
• Trochlear nerve malfunction
• Nystagmus may be produced voluntarily by some people.

SIGNS AND SYMPTOMS :

• Involuntary, side-to-side, up-and-down or circular eye movements in horizontal, vertical, or rotatory nystagmus respectively.
• These movements can be in one eye or even in both.
• Objects may appear shaky.
• Blurriness
• Night vision problems like Night blindness may also be one of the symptoms.
• Sensitivity to light

DIAGNOSIS:

If you feel any of the above symptoms, you might be having this eye condition of dancing eyes or nystagmus and must go to your ophthalmologist or optometrist for an eye exam as soon as possible to get the possible treatment. The doctor will test the following things:

• Special emphasis on recording the eye movements and then analyzing them accordingly. They may record movements by any special like an electronystagmograph (ENG) or by videonystagmograph (VNG). Doctor may also use an optokinetic drum or electrooculography.
• Will observe how the eyes focus, move, and function together to look for the problems that affects the control of the eye movements or make it hard to use both the eyes together.

•  Over the past 40 years, objective eye-movement-recording techniques have been used and successful as well as efficient in diagnosing the problem. Nystagmus should not be confused with the other superficially similar appearing disorders of eye movements like opsoclonus or ocular flutter. Objective eye-movement-recording techniques have great importance because without them it may be very difficult to distinguish nystagmus among these conditions.
• He/She may ask you to get some other tests done like, for example, neurological exam, brain MRI, brain CT scan, etc.

TREATMENT:

• Effect of nystagmus or ‘dancing eyes’ may be reduced by using doctor’s prescribed eyeglasses and contact lenses and can help to improve the vision but can’t cure it.
• Increased lighting may help in improving vision.
• Mini-telescopic eyeglasses may suppress the effect of nystagmus and again may improve vision.
• Sometimes surgical treatment is possible. Tenotomy is a commonly performed surgery that aims to reduce the eye oscillations which ultimately again results in improved vision.
• There are some drugs that may be used and could help in the condition. For example, In 1980, researchers discovered a drug called baclofen, some other drugs discovered later on which were found to be effective like memantine, levetiracetam, 3,4-diaminopyridine, etc.
• Acupuncture tests can also be one of the options for treatment. Benefits have been seen in some people in which their acupuncture points of the neck were used. Benefits include reduction in frequency & decreased slow phase velocities of the eye movements. Well some believe, results of these studies are clinically irrelevant.

 

PREVENTION :

Congenital nystagmus cannot be prevented because it is genetic, you might go for amniocentesis for gene testing before giving birth to the offspring that too isn’t proved anywhere because  Amniocentesis can't identify all genetic conditions and we don’t have much information regarding this so you must ask your doctor if this can be done or not.

But nystagmus can also be a sign of another underlying medical condition, so this can be prevented by  a comprehensive eye exam completed by a doctor to determine the cause and course of action or by going to the doctor specialized for the disease you are suffering so that he can guide you to “Do’s and Not to do’s “ to prevent nystagmus if that disease is one of the causes of nystagmus.