Nystagmus is a jerky involuntary repetitive oscillation of the eyeballs, which by their nature can be pathological and physiological. So, for example, nystagmus, which manifests itself in response to rotation in body space or an optokinetic drum, serves to maintain optimal vision and is perfectly normal. The movements of the eyes, which are carried out for fixation on the object, are called foveiruyuschimi, and movements that move the fovea away from the object - defoeivating. In cases of pathological nystagmus, each motor cycle of the eyeball usually begins with a spontaneous deviation from the object and the subsequent abrupt, reflex movement. In its direction nystagmus is nonspecific, torsion, vertical and horizontal, and according to the amplitude of oscillations - large-caliber medium-caliber and small-bore
Nystagmus - the causes of
Most often the development of nystagmus is due to the impact of local and central factors. Usually, this condition occurs when acquired in early childhood or congenital vision loss due to various eye diseases (retinal dystrophy, albinism, optic nerve atrophy, opacification of optical media, etc.), which leads to a violation of the mechanism of visual fixation
Nystagmus - Species
. → Pendulum nystagmus . Both defoeveirujushchie, and foveirujushchie movements are slow enough (in both directions speed nystagmus is identical)
• Acquired pendulum nystagmus has torsional, vertical and horizontal components. Congenital pendulum pendulous horizontal nystagmus, when viewed sideways, it can become jerky
• If the vertical and horizontal components of the pendulum nystagmus occur simultaneously (in phase), the perceived direction looks oblique
• If the vertical and horizontal components are not in phase, the perceived direction looks rotary or elliptical
. → Pinched nystagmus . It is determined quickly by a corrective jerky reflex motion with a slow "drifting" deflecting motion. Usually the direction of the nystagmus is indicated by the direction of the rapid component, as a result of which the jerky nystagmus is rotational, lower, upper, left-sided and right-sided. In addition, the jerky nystagmus is divided into nystagmus in case of paresis of the eye (most often a sign of brainstem lesion) and vestibular (setting)
включает в себя толчкообразный нистагм при боковом взгляде и первичный маятникообразный нистагм → Mixed nystagmus includes an ankle-shaped nystagmus with a lateral view and a primary pendulum-like nystagmus
– это толчкообразный нистагм, который вызывается изменением входа от вестибулярных ядер к воображаемым центрам горизонтальных движений глазных яблок. → Vestibular nystagmus is an impetuous nystagmus caused by a change in the entrance from the vestibular nuclei to the imaginary centers of the horizontal movements of the eyeballs. The rapid phase is initiated by the frontomesephalitic pathway and the brainstem, and the slow phase is initiated by the vestibular nuclei. Most often, rotatory nystagmus is associated with pathologies of the vestibular system. This kind of nystagmus can be caused by caloric stimulation:
• If you pour cold water into the right ear, a jerky left nystagmus appears
• If you pour in the left ear of warm water, you will see a jogging right-sided nystagmus
• If warm water is simultaneously poured into both ears, a nystagmus with a fast phase down will appear; cold water poured into both ears will lead to the appearance of an impetuous nystagmus with a fast phase upward
– это вызванный повторяющимися движениями наблюдаемого объекта в поле зрения толчкообразный нистагм. → Optokinetic nystagmus is caused by the repeated movements of the observed object in the field of vision, the jerky nystagmus. The eye movement following the object is a slow phase, and the saccular movement in the opposite direction, in which the eyes fix the next object - the fast phase. In the case of movement of the optokinetic drum from right to left, the left occipital parietal region controls the tracking (slow) phase to the left, while the left frontal lobe controls the saccular (fast) phase to the right. Optokinetic nystagmus is used to detect visual acuity in young children and to identify imitating simulators
– это небольшой по частоте толчкообразный мелкий нистагм при крайнем отведении взора. → The setting nystagmus is a small, jerky little nystagmus with an extreme gaze. Its fast phase in the direction of the eye
проявляется как следствие первичных дефектов эфферентных механизмов → Nystagmus of motor imbalance is manifested as a consequence of primary defects of efferent mechanisms
It is not combined with vertical deviation and is associated with infantile esotropia. Latent nystagmus is characterized by the following symptoms: nystagmus is absent when both eyes are open; when one eye is slightly opened, a horizontal nystagmus appears; A fast phase sets in on the direction of the unclosed fixing eye; in the case of covering one eye, the amplitude of the nystagmus increases
The type of inheritance is autosomal dominant or X-linked recessive. Congenital nystagmus manifests itself throughout life and appears on the second - third month from the moment of birth.
Symptoms of congenital nystagmus: an abnormal position of the head can be observed in the case of eye placement at the zero point (the direction of the view, in which the manifestations of the nystagmus are minimal); congenital nystagmus most often of an impulsive type, not noted in the phase of sleep, can be weakened by convergence
Very rare condition, which can be observed between three and eighteen months. To its reasons carry: a porentsefalicheskuyu cyst, a syndrome of an empty Turkish saddle and glioma of anterior sections of the optic path. Symptoms of a nodal spasm: a two-sided horizontal high-frequency fine-grained nystagmus with a nod of the head; torsion and vertical components can be observed; Nystagmus is often asymmetric, with an increased amplitude in lead
Periodic alternating nystagmus
The reasons for the development of this condition: ataxia-telangiectasia, demyelination, cerebellar disease, the effect of certain medications (phenytoin, etc.)
Symptoms: periodically received the opposite direction of the jerky horizontal nystagmus; each cycle is divided into a phase of immobility and an active phase; During the active phase, the speed, frequency, and amplitude of the slow phase initially progressively increase, after which it gradually decreases; after this there is a calm short interlude lasting from five to twenty seconds, eyeballs during which perform pendulum-like low-amplitude movements; After this, a cycle of consecutive movements in the opposite direction lasting from one to three minutes follows
Nystagmus - symptoms
In some species of the disease, high visual acuity persists, suggesting that the cause of nystagmus development lies in various regulatory disorders of the oculomotor apparatus.
Depending on the direction in which the vibrational movements occur, the horizontal (most often), vertical, rotational and diagonal nystagmus are distinguished. Unit by the nature of movements: jerky, mixed and pendulum.
The jagged nystagmus, starting from the direction of movement of its fast phase, is called right-or left-sided. With this type of pathology, there is a forced turn of the head to the side of the fast phase. In this turn, the person compensates the weakness of the oculomotor muscles, which leads to a decrease in nystagmus.
In the case of small-caliber nystagmus, the amplitude of the vibrational movements of the eyes is less than 5%, with a medium-gauge vibrational amplitude ranging from 5 to 15%, with large-caliber vibrational deviations exceeding 15%.
To determine the nature, frequency and amplitude of vibrational nystagmoid movements, a method of investigation such as nystagmography is used. In the absence of a nystagmograph, the amplitude is determined by the degree of displacement from the ophthalmoscope to the light reflex on the cornea. When examining patients with this violation, it is mandatory to conduct electrophysiological studies that determine the presence of amblyopia, the degree of organic damage and determine the tactics of future treatment
Nystagmus - treatment
Treatment of nystagmus is very laborious, difficult and often completely unsuccessful. All the efforts of many specialists are aimed at eliminating the root cause, which led to the development of this state. To reduce nystagmus, restore muscle tone and increase visual acuity, such therapeutic measures as reflexotherapy, keratoplasty, cataract extraction, eyeglass correction, treatment of amblyopia can lead.
Medical treatment of nystagmus is to improve the nutrition of all retina tissues and eyes (vitamin complexes, vasodilator drugs).
Surgical treatment of nystagmus is performed to reduce the vibrational movements of the eyeballs. The greatest effect is achieved only with horizontal nystagmus
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