Nystagmus

Nystagmus is an uncontrollable and involuntary (in rare cases voluntary) movement of the eyes. Movement can be horizontal, vertical, rotary, oblique, or a combination of these. Nystagmus is associated with malfunctions in brain areas responsible for controlling movement, but the exact nature of these abnormalities is not well understood.

Patients with nystagmus often put their heads in an abnormal position to improve their vision, negating as much of the effect of eye movement as possible. Nystagmus can also occur during the consumption of ecstasy, phencyclidine (PCP) or ketamine, although it is very sporadic and disappears with the effects of said psychostimulant.

Types

Nystagmus can be divided into two main types: infantile or congenital nystagmus and acquired nystagmus.

Congenital is generally associated with a severe lack of vision, it occurs in one in five thousand children and in 80% of cases it is a consequence of other diseases or conditions such as albinism. Congenital nystagmus frequently occurs spontaneously, without genetic ties, although sometimes the disease does exist in a family history. It manifests between eight and twelve weeks, although it has been documented in young people, so the term congenital might not be correct.

Nystagmus is also present in congenital neurological malformations of the craniospinal junction, such as Chiari malformation. This is one of the so-called rare diseases, and located at the base of the skull. 58% of the cases of live newborns with this disease suffer from nystagmus. It is also associated with diseases that the fetus obtains in utero transplacentally, such as parasitosis by Toxoplasma gondii, where the manifestations in the central nervous system are reflected in pathological conditions. like nystagmus.

The acquired is associated with neurological problems that occur during the life of an adult, such as a brain operation, a tumor, among others. Nystagmus can also be physiological (not pathological), due to movements of the inner ear. When we start a circular movement, the endolymph of the vestibular channels moves in the opposite direction, and so do the eyes. When the movement stops, the compensatory movements of the eyes also. It may be a manifestation of Wernicke's disease.

A slightly different type of nystagmus has been described whose main characteristic is its voluntary nature. The case of a 53-year-old woman capable of producing nystagmus voluntarily has been documented.

Causes

The causes of nystagmus may be congenital, idiopathic, or a pre-existing neurological disorder. This condition can also be temporarily induced by the effect of disorientation (such as after riding a roller coaster) or by certain stimulants or medications (such as alcohol, psychedelics, and dissociative drugs). This condition is not specific or characteristic of any other disease. Other possible causes are:

Diseases

Some of the following diseases have nystagmus as a pathological sign:

• Aniridia (lack of total or partial development of iris)
• Cranial trauma
• Brain tumor
• Wallenberg Syndrome
• Multiple sclerosis
• Infarction (the most common cause in older persons)

Stimulants

• Ebriety
• Benzodiazepines
• Barbiturates
• Ketamine
• Fenciclidina (known as PCP)
• Lithium
• Amphetamines

Other causes

• Non-psychological causes
• Troclear nerve diseases
• Strange objects in the eye

Treatment

Although some types of congenital nystagmus tend to improve with age, most do not have a definitive cure, however, the repercussions of the disease can be improved with appropriate therapy.

Treatments with drugs and surgery have been tried, surgery is used both to reduce the intensity of the nystagmus and thereby improve visual perception, as well as to improve the abnormal position of the head in case it occurs.

Ocular gymnastics visual therapy in a complementary way has shown to be useful. In the event of ametropia, the use of contact lenses adjusts better to eye movement, thus avoiding some prismatic aberrations induced by the decentration that exists due to eye movement. One advantage of contact lenses is that they move with the eye, thus improving image quality.

Part of the rehabilitation consists of reducing the amblyopia caused by the disease. Timely diagnosis and treatment preferably by a multidisciplinary team: optometrist, contactologist, pediatric ophthalmologist, strabologist, orthoptist and visual therapist is the best treatment option.

Occupational disease

Nystagmus is recognized as an occupational disease of miners, according to the Spanish table of occupational diseases. At the work level, a rotation of exposed personnel or a reduction in exposure periods can delay this disease, accompanied by a medical program preventive.