Definition
Definition
Nystagmus is an involuntary movement of both eyes, with low amplitude oscillation and rotation of the eyeball.
Classification
There are several types of nystagmus (non-exhaustive list):
- Physiological nystagmus :
- Optokinetic nystagmus or railroad nystagmus. This variety of nystagmus occurs when the patient's eyes focus on moving images. It consists of a series of slow saccades of the eye, which follows the moving object, and a rapid jerk that seems to recall the eyeball.
- Vestibular nystagmus is secondary to transient excitation or paralysis of one or both labyrinths of the inner ear, following an injection of cold or warm water into the ear.
- Pathological nystagmus :
- Acquired nystagmus, the origin of which is neurological (multiple sclerosis, you die of the brain, damage to the cerebellum) is accompanied by disorders of hearing.
- Nystagmus due to a cataract (opacity of the lens).
- Nystagmus secondary to Toxoplasmosis (infectious disease caused by a parasite transmitted by cats, among others).
- Nystagmus due to a hydrocephalus (increase in cerebrospinal fluid in the central nervous system).
- Nystagmus occurring after a strabismus (the vision axes are not parallel).
- The consecutive nystagmus of albinism (absence or reduction in the quantity of melanin pigments).
- Nystagmus due to damage to the retina.
- Congenital spring nystagmus, characterized by eyes moving slowly in a horizontal direction, then much more quickly in the opposite direction. Congenital nystagmus tends to increase with asthenia (fatigue), some anxiety, or when the patient is asked to concentrate. This type of nystagmus can develop into a torticollis, due to the fact that the child tries to block his nystagmus by always turning his head to the same side.
- Miners' nystagmus is caused by poor lighting and the efforts these deep-sea workers make to accommodate. Furthermore, the upward and inward gaze direction favors the occurrence of this pathology, which should be considered an occupational disease.
- Nystagmus due to thiamine deficiency: Also known as vitamin B1, thiamine, which is water-soluble, is essential for the proper functioning of chemical reactions involving carbohydrates. It also plays a role in regulating the activity of the nervous system.
- Drug-induced nystagmus in people using medications to combat seizures.
Medical exam
Additional examination
Electrical recording of eye movements ( electronystagmography ) establishes, in almost all cases, a differentiation between the different forms of nystagmus.
Treatment
Treatment
The treatment is that of the condition in question:
- Medical, by port of corrective lenses comprising prisms temporary or permanent. In cases of congenital nystagmus, the prescription of corrective prism lenses eliminates the incorrect position of the head. The optical correctors used (adhesive, if temporary, and in the lens when it is permanent) cause a forced deviation of the 2 eyes, which in a way forces the child to turn his head.
- Surgical depending on the type of nystagmus and its cause: it sometimes allows a certain definitive improvement.
- By physiotherapy : a physiotherapist specializing in the treatment of dizziness, and instabilities can perform the rehabilitation of a nystagmus pathology of peripheral origin with damage to theinner ear or vestibular nerve. To understand the function of the vestibular nerve, it is necessary to know that the bony labyrinth (which is the set of cavities constituting the inner ear) is divided into three parts:
- The membranous labyrinth consists of a network of small pockets containing endolymph (lymphatic fluid) and including the semicircular canals (which are the organs of balance), the vestibule (with the utricle and the saccule) as well as the cochlear duct (which is the organ of hearing). Other nystagmus can also be treated by the physiotherapist, but the two types of nystagmus mentioned above are more receptive to this specific work. The basic exercises are:
- Rotations on a rotary chair (vestibular nystagmus training)
- Balancing exercises in a darkened room while watching a parade of small light spots projected onto the walls (optokinetic nystagmus training).
- According to some authors, the results obtained through this rehabilitation are good. Indeed, the pathological nystagmus and the accompanying vertigo disappear gradually as the sessions progress.
References
Bibliography
- Leigh RJ. Zee DS: The Neurology of Eye Movements, 2nd ed. Philadelphia, Davis, 1991
- Miller NR: Walsh and Hoyî's Clinical Neuroophthalmology, 4th ed. Baltimore, Williams & Wilkins, 1982
- Cyril Dumergue, Private Physiotherapist in Pont-de-Claix.