Eye Jerking Disorder: Its Description, Signs, Root Causes, and More Insights
Nystagmus is a condition characterised by uncontrollable, often rhythmic and rapid eye movements. This condition can be broadly categorised into congenital (infantile) and acquired types, each with distinct causes, symptoms, diagnostic approaches, and treatments.
Types
Congenital Nystagmus
Also known as infantile nystagmus syndrome (INS), congenital nystagmus typically begins before 6 months of age. It is often associated with sensory deficits such as albinism, congenital cataracts, or retinal dystrophies, or idiopathic/genetic causes. Congenital nystagmus commonly presents as horizontal oscillations.
Acquired Nystagmus
Acquired nystagmus develops later in childhood or in adulthood. It can have multiple forms (jerk, pendular, mixed) and planes (horizontal, vertical, torsional). Acquired nystagmus is often associated with neurological or vestibular disorders.
Causes
Congenital Nystagmus
Congenital nystagmus can be caused by genetic mutations affecting motor or sensory pathways. Sensory deficit nystagmus may result from vision deprivation from birth conditions like albinism, cataracts, or retinal disease. Motor nystagmus may result from central neurological or ocular motor system dysfunctions.
Acquired Nystagmus
Acquired nystagmus can be caused by neurological insults such as stroke, multiple sclerosis, brain tumors, or head trauma. Vestibular disorders like Ménière’s disease or labyrinthitis can also cause acquired nystagmus. Toxic or metabolic causes such as side effects of medications, vitamin deficiencies, alcohol or drug use can also lead to acquired nystagmus.
Symptoms
Congenital Nystagmus
In congenital nystagmus, involuntary eye movements are noticed soon after birth. Vision may be blurry or decreased, but usually no oscillopsia (visual environment appears stable). Abnormal head posture or head nodding to reduce eye movement effects may also be observed.
Acquired Nystagmus
Acquired nystagmus can cause sudden or gradual onset of involuntary eye movements. Oscillopsia is common, a sensation that the visual scene moves or bounces. Possible dizziness, balance issues, or vertigo may also be present if vestibular related.
Diagnosis
Diagnosis of nystagmus involves a comprehensive eye exam, noting eye movement type, amplitude, and frequency. A detailed medical history, including onset age, associated conditions, and family history, is also crucial.
For congenital nystagmus, the focus is on detecting associated sensory deficits and observing head posture and vision function. Ocular tests like OCT and ERG assess retinal structures and function. Genetic testing may also be conducted if hereditary forms are suspected.
For acquired nystagmus, neuroimaging (MRI) is used to exclude neurological causes such as stroke or tumour. Vestibular assessment is conducted if balance issues are present. Blood tests for metabolic or toxic causes and a medication history review are also important.
Treatment
No cure for nystagmus itself exists currently. However, treatment goals are to improve vision, reduce oscillopsia, and manage underlying conditions.
For congenital nystagmus, optical corrections (glasses or contact lenses) are often the best treatment, as they aid vision but do not eliminate the condition. Prisms can also be used to shift the "null point" where eye movement is minimal. In some cases, medications such as memantine or gabapentin may be used. Surgical procedures like tenotomy or Kestenbaum surgery can help align eyes and reduce abnormal head postures. Genetic counseling may also be beneficial for inherited forms.
For acquired nystagmus, addressing treatable causes such as underlying medical conditions, alcohol or drug use, can help resolve nystagmus in some people. Symptomatic medications (gabapentin, baclofen) can reduce nystagmus intensity. Vestibular rehabilitation therapy may also be beneficial if balance is affected.
Additional Notes
In conditions like albinism, nystagmus may be partly due to altered motor neuron innervation and neuromuscular junction abnormalities of extraocular muscles, indicating central neurological involvement early in development. Nystagmus may also be associated with muscle fiber abnormalities in congenital muscle disorders affecting eye movement, highlighting complex neuromuscular contributions.
This overview synthesizes the distinction between congenital and acquired nystagmus, outlining their causes, symptoms, diagnostic methods, and treatment options based on recent clinical and research data. Other types of nystagmus include vertical and rotary. Certain drugs such as gabapentin, baclofen, and memantine can reduce the effects of acquired nystagmus. Practicing self-care such as yoga, tai chi, pilates, relaxation, meditation may help lessen the impact of nystagmus on vision, although scientific data is limited. A doctor may diagnose nystagmus through a comprehensive eye exam, medical history, visual acuity assessment, measurements for corrective lenses, analysis of eye movement, focus, and coordination, referrals for ear or neurological exams, MRI scans of the brain, and more.
- The uncontrollable, rhythmic eye movements associated with medical-condition vertical nystagmus can indicate neurological or vestibular disorders, as is the case with acquired nystagmus.
- In some cases of congenital nystagmus, which is typically characterized by horizontal oscillations and commons in early childhood, sensory deficits such as albinism, congenital cataracts, or retinal dystrophies, point towards mental-health and eye-health issues.
- Proper diagnosis of nystagmus involves both eye-health and medical-condition assessments, including a detailed medical history, comprehensive eye exam, and neuroimaging to rule out neurological causes such as stroke or tumor, reflecting the interplay between health-and-wellness and neurological-disorders.
