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If a person cannot focus on one point due to the fact that his eyeballs make involuntary oscillatory movements, it is highly likely that this is nystagmus.
Nystagmus of the eyeball – what is it?
With nystagmus, the eyeballs repeat the same vibrations, and this process cannot be controlled by any effort. Nystagmus occurs even in healthy people after a rapid rotation of the body, or when following a rapidly moving object with a glance. However, most often this pathology is based on damage to the central nervous system, disease of the inner ear, visual impairment.
If nystagmus arose due to a violation of the functionality of some organ, it is necessarily accompanied by a decrease in visual acuity. The proportion of eyeball nystagmus among all eye diseases is 18%, among visually impaired children from 20 to 40% of patients suffer from nystagmus.
The eyeballs make spontaneous movements due to an increase in tone on one side of the labyrinth of the inner ear. Normally, the signal transmitted from this vestibular analyzer reaches the eyeballs at the same speed. This synchronicity allows the eyes to make the same movements or remain at rest. With a disease, hypertonicity of the labyrinth of the inner ear disrupts the coherence of the signals of the vestibular apparatus, the eyeballs involuntarily oscillate in different directions.
If nystagmus appears when you change the position of the body, then the pathology has spread to the semicircular canals of the inner ear.
The symptom is nystagmus
The manifestations of the disease depend on its type. Since nystagmus occurs against the background of the underlying pathology, at the same time the patient experiences the full severity of the symptoms of the underlying disease. Common to all types of nystagmus is an oscillatory movement of both eyeballs, which is uncharacteristic for a healthy person, which can be both friendly and multidirectional. They move in a circle, diagonally, up and down, or left and right.
Additional symptoms:
Frequent dizziness;
Light sensitivity;
Violation of the process of adaptation to changes in external conditions;
The blurriness of objects that fall into the field of view, or their trembling.
If the patient changes the direction of the gaze, the position of the head, or focuses the gaze on the object as much as possible, the amplitude of the oscillations of the eyeball decreases slightly, although it cannot be completely stopped.
To reduce the manifestations of nystagmus, the patient tries to take exactly the position of the head, in which the movements of the eyeball are minimal, its accommodation improves. Most often, these are tilts or turns of the head to the side. Symptoms of the disease are aggravated by stress and excitement, during fatigue. These manifestations are affected by a change in mood, the size and brightness of the object, and visual concentration.
Eyeballs can make the same movements, or move in different directions with different vibration patterns.
The nature of movements with nystagmus:
Pendulum – with the same amplitude;
Jerky – in one direction the eyes move slowly, and in the other quickly;
Mixed – both types of oscillations occur in one case.
In addition to local clinical manifestations, the patient has general symptoms of the disease – weakness of muscle tone, unsteady gait, hearing loss on one or both sides, deterioration in general well-being.
Causes of nystagmus
The basis of congenital nystagmus is a violation of the functioning of the central nervous system. Clinical symptoms appear against the background of albinism or congenital damage to the photosensitive cells of the retina (Leber’s amaurosis).
Causes of acquired nystagmus:
Traumatic brain injury with damage to the occipital zone of the cerebral cortex or optic nerve;
Consequences of a stroke or multiple sclerosis;
Malignant brain tumor;
CNS intoxication with alcohol, overdose of barbiturates or anticonvulsants;
Trauma or disease of the inner ear;
Reduced visual acuity with cataracts, eye injury, or complete blindness;
Birth trauma, pathology of the prenatal period;
Consequences of neuroinfections affecting the cerebellum, cerebral cortex, medulla oblongata.
In a healthy person, nystagmus of the eyeball occurs when orientation in space is disturbed, and disappears in a calm state. If recovery does not occur, then the nervous system is not able to return to its previous positions due to pathology.
Types of nystagmus
Specialists divide nystagmus into congenital and acquired forms. Congenital nystagmus is divided, in turn, into latent and manifest-latent types, and acquired – into neurogenic and vestibular types.
horizontal nystagmus. With this type of pathology, the movements of the eyeball are directed horizontally, that is, to the right and left. Most likely, the cause of the disease is a lesion of the inner ear or the middle sections of the rhomboid brain, which connects the head and spinal sections of the central nervous system.
vertical nystagmus. With vertical nystagmus, the eyeball moves vertically, that is, up and down. Appears when the dosage of barbiturates is exceeded or pathologies of the upper part of the brain stem.
Rotary nystagmus. Torsion, or rotator nystagmus, appears with the rapid rotation of the body around its axis. The eyeball immediately after stopping moves in the opposite direction, during rotation it makes movements with a large amplitude in the direction of rotation.
Spontaneous nystagmus. With spontaneous nystagmus, the eyeballs involuntarily move at a high frequency. A spontaneous form of nystagmus can be diagnosed in a healthy person when he watches a fast moving object or spins at high speed himself. Most often, the direction of movement of the eyeball occurs in the horizontal plane.
Distinguish jerky and pendulum type of spontaneous nystagmus:
Pendulum nystagmus – eye movements resemble a sinusoid or the swing of a pendulum;
Jerky nystagmus – the eyeball moves quickly in one direction and slowly in the other.
Due to a very low level of vision (more than 6 diopters), nystagmus can be manifested by a violation of gaze fixation.
small-scale nystagmus. With this type of nystagmus, the eyeballs make a small amplitude of oscillation (no more than 5-6 °) in the horizontal direction. The disease is directly related to the pathology of the inner ear, its labyrinth. The movement of the eyeballs is involuntary.
Installation nystagmus. With this form of pathology, the eyeball makes small-scale rhythmic movements that occur when looking away to the side, when the eye muscles are extremely tense.
congenital nystagmus. This type of visual anomaly manifests itself immediately after the birth of a child, retains its symptoms throughout a person’s life. Most often takes a horizontal or jerky form.
Varieties of congenital nystagmus:
Optical – one of the severe visual disorders, diagnosed at 2 months of a child’s life, has a pendulum shape, the range of motion decreases when trying to focus on one object;
Latent – the disorder occurs when trying to close the eye with the eyelid in a child with strabismus, takes a jerky form, the fast phase of movement is directed towards the open eye;
Nodding spasm is a rare visual disorder, diagnosed at the age of 4-14 months, its characteristic symptom is torticollis, mismatch between head movement and eye movements.
Degree of nystagmus
There are 3 degrees of nystagmus:
If the eye is at rest, nystagmus is absent, but manifests itself with extreme abduction of the organ of vision in the direction of the fast phase.
Pathology manifests itself when the eye is in a central position.
Nystagmus occurs when the eye is moved to the side of the slow phase. In the third degree, the eyeball oscillates in the opposite direction.
Diagnostics
The main method for diagnosing nystagmus is an examination by an ophthalmologist with the determination of the visual acuity and field of vision of the state of the fundus and the optical media of the eye. The doctor immediately notes the presence of involuntary eye movements, asks the patient to fix his gaze on the tip of a pencil or a special pointer. The ophthalmologist moves the pointer in different directions, using this technique, sets the type of nystagmus.
Additional diagnostic methods:
Magnetic resonance or computed tomography – helps to determine the presence or absence of brain tumors, as a possible cause of nystagmus;
Microperimetry – used to determine the parameters of nystagmus, to study the sensitivity of the retina;
Echoencephalogram (echo-eg);
Refractometry – used to determine the type of refraction, the presence of myopia, hypermetry;
Electroretinogram;
Electronystamography – is used to determine the potential difference between the cornea and the retina, an increase in which is characteristic of this pathology;
Blood test to determine the concentration of toxins in the body;
Determination of visual evoked potentials;
Consultation of a neuropathologist, otolaryngologist and neurosurgeon.
Visual acuity is determined in different situations – with and without glasses, with a normal head position or in a forced position. With a detailed examination, the doctor can detect atrophy of the optic nerve, pigmentary retinal degeneration, clouding of the lens and cornea, macular coloboma in a patient.
Treatment of nystagmus
To eliminate nystagmus, the doctor treats the underlying disease that caused the pathology. Therapy of the disease is quite long and complicated, it includes optical vision correction, drug treatment, and surgical methods.
optical correction. To smooth visual acuity disturbances, the doctor carefully selects glasses or contact lenses for the patient to examine objects near and far. If the patient suffers from albinism, retinal dystrophy or optic nerve atrophy, glasses with orange, yellow, brown or neutral light filters are used. Dense light filters protect the eyes from the negative effects of the environment, provide the most possible visual acuity.
Pleopathic treatment. To normalize amblyopia and increase the accommodative capabilities of the eyes, retinal stimulation exercises are prescribed:
Glare on a monobinoscope using a red filter to stimulate the central part of the retina;
Color and contrast-frequency tests on a computer and an illusion device (spider, zebra, crosses).
To reduce the amplitude of nystagmus and increase the level of vision, diplopiac treatment methods are used:
Binarimetry;
binocular exercises.
The method of applying the exercises provides for their implementation first for each eye separately, then for both eyes at the same time.
Drug treatment. Treatment with drugs is not the main method, it is auxiliary.
The main groups of drugs:
Vasodilators – Theobromine, Cavinton, Angiotrophin, Trental;
Preparations for improving the nutrition of the eye – Actovegin;
Multivitamins.
Nystagmus surgery
Correction of nystagmus in the punctate form of this pathology consists in weakening the strong muscle on the side of the strong phase and strengthening the weak muscle on the side of the weak phase. Thus, the median position of the relative rest of the eyes is fixed:
Operation steps:
Bilateral symmetrical intervention (recession) on the muscles responsible for the slow phase.
With a sharp decrease in nystagmus, the second stage is not carried out. If there is no effect, a bilateral symmetrical intervention (recession) is performed on the muscles responsible for the fast phase.
When nystagmus is combined with strabismus, a smaller resection is performed on the side of the deviation, a large resection is performed on the side opposite to the deviation. The use of laser and radiotherapy methods allows you to save the nerve endings and blood vessels of the eyes as much as possible. After surgery, it is required to consolidate the results with conservative therapy methods.
According to medical statistics, successful rehabilitation is guaranteed in 78% of cases of surgical intervention. The patient gets the opportunity to have an even look with confident fixation on the object, high visual acuity without the use of glasses, the ability to perceive 3D format.
Complications of nystagmus
The most common complication of nystagmus is strabismus, or strabismus, in which the eyes look in different directions, and the axes of gaze cannot be brought to one point.
Other complications:
Amblyopia is a unilateral visual impairment in which one eye does not participate in the process of vision, is inactive;
Astigmatism – light rays scatter and create a blurry image on the retina;
Dizziness;
Headache;
Impaired coordination of movements;
Compensatory torticollis, arising from the need to keep the head in an unusual position;
Labyrinthitis is an inflammation of the tissues of the inner ear.
Nystagmus in children
Immediately after the birth of a child, it is impossible to immediately diagnose nystagmus, since newborns are characterized by a lack of gaze fixation on an object. If at the age of 1-1,5 months the baby does not fix his gaze on the toy, the ophthalmologist may suspect eyeball nystagmus in the child.
You can definitely say this in the second or third month of a child’s life. In the first year of life, the visual apparatus is still developing, so up to a year the diagnosis of “nystagmus of the eyeball” is not made for babies, until this age it is not considered a deviation. If there are strong prerequisites for making this diagnosis, a neuropathologist and an ophthalmologist monitor the child’s health.
Possible causes of nystagmus in children:
Pathology of intrauterine development;
Birth injury;
Albinism.
To preserve the visual acuity of the child, he is carefully examined, wearing special glasses and other complex measures (hardware and surgical treatment) are prescribed. If the treatment is carried out correctly and in a timely manner, visual acuity in children does not deteriorate.
Prognosis of the development of the disease
Nystagmus of the eyeball with adequate treatment of the underlying pathology that caused visual impairment can be eliminated almost completely. Visual functions are restored, the quality of life does not suffer.
To prevent the occurrence of nystagmus, it is necessary to diagnose and treat pathologies of the brain, eyes and inner ear in a timely manner. If nystagmus appeared as a complication, in patients taking hypnotics and anticonvulsants, a dosage adjustment of the drug is required.
Author of the article: Degtyareva Marina Vitalievna, ophthalmologist, ophthalmologist