Nystagmus block syndrome
Introduction
Introduction to nystagmus syndrome Nystagmus blockage syndrome (NBS) is a special type of strabismus characterized by early occurrence of nystagmus in the infant with esotropia, compensated head position and pseudo-entropy. basic knowledge The proportion of illness: 0.001% Susceptible people: no special people Mode of infection: non-infectious Complications: Amblyopia
Cause
Causes of nystagmus syndrome
Cause:
Clinically common congenital nystagmus is accompanied by a compensatory head position, so that both eyes are in the right or left position. At this time, the intensity of the nystagmus is the lightest or disappears, thereby improving the vision. This position is called the resting eye position. Neutral zone or null zone, but there is a congenital nystagmus. When the eye is in the internal or internal oblique position, the nystagmus is reduced or disappeared. When moving to the first eye position and the outer rotation position, the nystagmus becomes more and more obvious. For congenital nystagmus, whether it uses internal rotation or binocular convergence to suppress nystagmus, Adelstein and Cüppers think that it may be internal rotation instead of convergence. Neutralization of nystagmus, because the internal rotation does not involve regulation, but the result of von Noorden observation is that the congenital nystagmus patient during the episode of intermittent esotropia, the pupil becomes smaller, suggesting that it is related to the mechanism of convergence regulation.
Prevention
Ocular tremor block prevention
A reasonable diet can take more high-fiber and fresh vegetables and fruits, balanced nutrition, including essential nutrients such as protein, sugar, fat, vitamins, trace elements and dietary fiber, with a combination of vegetarian and vegetarian foods. The complementary role of nutrients in food is also helpful in preventing this disease.
Complication
Complications of nystagmus syndrome Complications amblyopia
Amblyopia is more common.
Symptom
Symptoms of nystagmus syndrome common symptoms vestibular reflex disappears nystagmus astigmatism
The main symptoms
(1) nystagmus: before astigmatism occurs in the strabismus, it is a congenital impulsive type of dominant nystagmus (rare recessive), and the nystagmus intensity and amplitude are reduced or disappeared during intraocular transposition (internal strabismus or convergence); When the eye is separated or covered, a horizontal nystagmus occurs when the inner eye turns into a positive position; when the eye rotates outward, the nystagmus is obviously aggravated.
(2) esotropia: more esotropia occurs in infancy, occurs after nystagmus, is non-adjusting, the angle of internal oblique is inversely proportional to nystagmus, that is, when the number of internal slope increases, the intensity of nystagmus decreases or disappears, and visual acuity increases; When the number of internal slopes decreases, the nystagmus intensity increases and vision decreases.
(3) Compensatory head position: When the binocular vision is close, the patient sometimes looks at the right eye, takes the head position facing the right turn, and sometimes the left eye gaze and takes the head position of the left turn; when the vision difference between the eyes is large, the patient Maintaining the internal rotation position with the gaze eye, the head position turns to the gaze side, that is, the eyesight is good to gaze at the eye side, so that the inner rotation eye is directly facing the front, even if the other eye is covered or the other eye is added with the equal angle of the prism. The head position is basically unchanged.
(4) pseudo-extraocular muscle paralysis: when the eyes are in the same horizontal motion and the visual acuity is similar, often use the inner eye to gaze, the external rotation is insufficient, and the nerve is paralyzed; if the single eye (covers one eye) rotates horizontally, Turned to normal.
Accompanying symptoms
(1) More monocular: often combined with monocular amblyopia, this point is different from infantile strabismus.
(2) AC/A ratio is normal: if there is a change in hyperopic diopter, it does not match esotropia.
(3) Other strabismus (DVD, etc.) and abnormal nervous system types can be combined. von Noorden reported that the incidence of neurological abnormalities was 25% in 84 cases of nystagmus syndrome.
(4) The surgical effect is difficult to estimate: the intraocular rectus retraction in both eyes is better than the single eye retreat plus shortening surgery, but the postoperative overcorrection, undercorrection and reoperation rate are higher, that is, the surgical effect is difficult to control.
Clinically, infantile strabismus with nystagmus is present. When there is horizontal compensatory head position, attention should be paid to whether there is this disease. In addition to the above typical features, a prism test should be performed: according to the Hering rule, when one eye is right or left When turning, the other eye must also move to the right or to the left, that is, each eye movement must have the same intensity, and the same effect of the nerve impulse reaches both eyes at the same time, such as placing the 50 prism bottom outward. In front of the eyes, the eye is moved to the target, the eyeball will move toward the tip of the prism, and the gaze of the patient with nystagmus syndrome will remain in the original internal rotation position, and the other eye will not make an obvious external rotation movement, and the compensatory head position No change.
Examine
Examination of nystagmus syndrome
No special laboratory tests, eye movements, eye position and eye movements are required.
Diagnosis
Diagnosis and differentiation of nystagmus syndrome
Because the intrinsic complication is combined with infantile strabismus, it should be differentiated from infantile strabismus and bilateral nerve palsy.
1. Infant-type esotropia: The disease is mostly alternating esotropia. When the eyeball is in the first eye position or the external position, there is no nystagmus; due to alternating gaze, monocular amblyopia rarely occurs; The non-gaze eye is the internal rotation position, and there is no compensatory head position; the 50 triangular prism bottom is placed outwardly on the gaze eye, and the other eye is used for the same amount of motion, and the surgical effect is reliable.
2. Bilateral nerve paralysis: This disease, whether the eyes move horizontally or monocularly, is manifested as insufficient external rotation. Under the general anesthesia, congenital bilateral paralysis shows that the esotropia does not disappear, and the nystagmus syndrome The performance of the esotropia can disappear, this point is the main point of discrimination.
