2DefinitionNystagmus is an involuntary rhythmic shaking or wobbling of the eyes. The term nystagmus is derived from the Greek word ‘nystagmos’ which was used to describe the wobbly head movements of a sleepy individual.
3Classification of Nystagmus Doctors and researchers classify nystagmus by the characteristics of the eye movements like:back and forth like a pendulumslowly in one direction and then rapidly in anotherlaterally or vertically and by how muchhow fast do the eyes move
4Classification of Nystagmus However there are over 45 types of nystagmus but traditionally nystagmus has been divided into two groups:sensory nystagmus (congenital): that begins very early in life and is related to vision loss.motor nystagmus (acquired): and is associated with neurological disorders and control of muscle function occurring later in life.
5Congenital NystagmusCongenital nystagmus occurs more frequently than acquired nystagmus. It can be insular or accompany other disorders.Types of congenital nystagmus include:albinism, aniridia, optic nerve hypoplasia, achromatopsia, congenital cataracts, retinopathy.
6Pendular NystagmusThe most typical nystagmus related to vision loss during childhood is a pendular nystagmus. The eyes rotate back and forth evenly, much like a pendulum.
8Acquired NystagmusNystagmus can be acquired later in life due to neurological dysfunction, diseases or toxicity such as:cerebellar ataxiathalamic hemorrhagea head injurystrokemultiple sclerosisbrain tumorsalcohol intoxication
9Acquired NystagmusUnlike nystagmus acquired from early in life, patients with late onset nystagmus usually notice movement in their vision related to the movement of their eyes. This is called oscillopsia. Oscillopsia causes a person to have dizziness related to the new movement they experience in their vision.Late onset nystagmus is more likely to be directional. The eye will move slowly in one direction, then quickly move back.The nystagmus may change as the patient looks in different directions.The unexplained onset of nystagmus in an adult may indicate a serious neurological disorder and an immediate examination is indicated.
11Horizontal Pendular Nystagmus Most frequently, horizontal or pendular nystagmus is caused by:central lesions involving the central tegmental tractdamage of the cerebellar nucleilesion near the oculomotor nuclei
13Vertical Pendular Nystagmus Vertical nystagmus occurs much less frequently than horizontal nystagmus and is often, but not necessarily, a sign of serious brain damage. TThe most common cause vertical nystagmus that frequently appears after:pontine hemorrhage related to damage to the central tegmental tract.toluene sniffing, glue sniffing, usually in accompaniment with cerebellar deficits
15See saw NystagmusSeesaw or jerk nystagmus is a rare binocular disorder characterized by alternating vertical skew deviation and conjugate ocular torsion. Jerk seesaw consists of torsional slow phases in one direction and quick phases in the opposite.
17Fluctuations in Vision Nystagmus patients often experience fluctuations in their vision. A change in the speed of the nystagmus leading to a decrease in vision can be related to:stressthe patient’s emotional statefatiguethe direction of view
18The Null PositionPatients with nystagmus often find a unique position of their head and eyes that slows the nystagmus allowing them to have better vision. This is called a null position and varies with each person.
19TreatmentCongenital nystagmus has traditionally been viewed as non-treatable, but medications have been discovered in recent years. Several therapeutic approaches are also proposed, such as:contact lensesdrugssurgery
20TreatmentGabapentin, an anticonvulsant, was found to cause improvement in about half the patients who received it to relieve symptoms of nystagmus.Other drugs found to be effective against nystagmus in some patients include:memantinelevetiracetamacetazolamide
21TreatmentClinical trials of a surgery to treat nystagmus known as tenotomy. Tenotomy aims to reduce the eye shaking (oscillations), which in turn tends to improve visual acuity.