phoria
Introduction
Introduction to strabismus Occult strabismus is a potential eye position deflection, but can maintain binocular monocular vision under the control of fusion reflex, to force the two eyeballs to remain in the positive position without showing skew, once the brain fusion is blocked (such as one eye) When covered (or covered) or out of control (such as in excessive use of eyesight or mental fatigue), eye position deflection will manifest. Therefore, between the squint and the squint, it is only a degree rather than a qualitative difference. basic knowledge The proportion of the disease: the incidence rate is about 0.001% -0.002% Susceptible people: children Mode of infection: non-infectious Complications: headache, nausea and vomiting
Cause
Cause of strabismus
(1) Causes of the disease:
The etiology of the occlusion is not fully understood. From the etiology, the occlusion caused by the imbalance of the extraocular muscle can be divided into three aspects: the local anatomy of the eye is abnormal, so that the eye movement is blocked by structural factors. (static slant); 2 due to refractive abnormalities caused by regulation and set imbalance (dynamic slant); 3 extraocular muscle coordination due to weakness, excessive excitement or neuromuscular dysfunction was disrupted (neural occultation) oblique).
(2) Pathogenesis:
1. Static slanting: static heterophoria or anatomic heterophoria, the local anatomical relationship between the eyeball and its appendages is the primary in determining the position of the eyeball and its free movement. Only when these factors are relatively normal and close to symmetry can the two eyes maintain the orthodontic movement of the eyes or completely. Since such complete symmetry is rare, it is obvious that this is the basic cause of occlusion, common anatomy Factors include: asymmetry of the eyelids, abnormalities in the shape of the sacral wall or skull, or abnormalities in the shape of the eyeball (such as high myopia) and abnormalities in the volume of the eyeball or swelling of the contents or displacement of the eyeball, so that the free movement of the eyeball is Inhibition, but the most common is the abnormality of the muscle, including the obvious length, the movement, the change of the volume and the attachment point of the sclera, the attachment point of the medial rectus muscle is higher, and the attachment point of the lateral rectus muscle is later, it is easy to produce the implicit oblique The medial rectus muscle is weak or the attachment point is relatively posterior, the lateral rectus muscle is stronger or the attachment point is higher, and the external oblique is easy to occur; the anatomical abnormalities or attachment points of the upper and lower rectus muscles or the superior and inferior oblique muscles It is a cause of upper slanting. These and other small changes do not cause strabismus. With age, the ability to coordinate is weakened, the function of the organ is changed, and the muscles and ligaments are lack of flexibility. Balance will occur and expand, and the disease and function decline of the muscle itself must also be included. Finally, the abnormal Alpha angle caused by the abnormality of the macular position will cause difficulty in the joint of the binocular visual axes. The slant caused by these structural factors can be Common or non-common, the imbalance of the eyes in different gaze directions can be asymmetric.
2. Dynamic slanting: kinetic heterophoria, also known as accommodational hetemphoria, is due to the inconsistency of regulation and convergence, most of the extraocular muscle imbalance It is caused by the disorder of coordination and convergence of the convergence. Usually, the relationship between regulation and aggregation (AC/A ratio) is relatively fixed. If the ratio is not normal, the set caused by each diopter adjustment is too small or too much; Corrected refractive error can also break the balance of the AC/A ratio, because the set needs to be changed in order to see the object at a certain distance. Sometimes the abnormal AC/A ratio and the uncorrected refractive error can be simultaneously Existence, the inconsistency between regulation and aggregation promotes the development of dynamic slanting. When the patient cannot adequately control the slanting, in order to obtain clear binocular monocular vision, the kinetic fusion reflex compensates for the abnormal AC/A ratio. As for perceptual sexual integration, it continues to be at different levels of difficulty, which will inevitably lead to its excessive use.
Therefore, when anatomical or innervation factors do not work, in patients with moderately hyperopic eyes without correction, too close work in the emmetropic eye, or in acquired presbyopia, due to the need to increase adjustment, there will be It develops into a tendency of intrinsic slanting. Congenital myopia is often over-collected due to closeness, and it may also develop into an implicit slant. Conversely, congenital astigmatism or acquired myopia does not require adjustment, and the developed aging eye does not need to be assembled. Mixed astigmatism or high astigmatism does not need to be adjusted or aggregated. In these cases, external oblique slanting can occur. Therefore, when doing squint examination, anyone with ametropia should wear corrective glasses to check, such as a new wearing mirror. Accurate results should be obtained after 4 weeks of wearing the mirror and then checking.
3. Neurogenic slant: The slant caused by the abnormal innervation of the extraocular muscle is called neurogenic heterophoria, which includes many factors: the eye muscles are paralyzed or the sputum condition affects the underlying neurons. Abnormal or irregular stimulation of low-level coordination areas, disturbing the proprioceptors that connect the eye movement organs, or the imbalance of the high-level center, all of which cause paralytic or spastic strabismus have little effect on eye movement, in order to maintain The fusion motion can be controlled to make the skew become potential when the eyes are gazing.
Clinically, this kind of slanting is divided into two categories.
(1) Sub-nuclear slant:
Because the subordinate neurons are involved in the occlusion caused by a single extraocular muscle dysfunction, often non-common occult, this slant is mostly temporary, if the extraocular muscle function is fully restored, the slant can disappear, but The recovery of function is often incomplete or undergoing some changes, including the contraction or extension of muscles and ligaments, and leading to permanent skewness, and most of the transition to common slanting, it is worth noting that the movement of the eye requires only any muscle. A little strength, the deviation is not due to the weakening of the function of a single muscle, but the imbalance of the distribution of neuromuscular coordination functions. In addition, the complete common slant is rare, and even if there is, it gradually changes.
(2) Nuclear slanting:
Due to the slanting of the superior neuronal lesions, most of them are common slanting, which may involve the same direction movement or the anisotropic movement. If the degree is slight, the slant is oblique.
In addition, the cause of occlusion is closely related to the strength of fusion function: both kinetic fusion and perceptual fusion are related to slanting. If the fusion function is well developed, the fusion range is large, and even if there is skew, it can be fused. Conversely, if the fusion function is not well developed, a mild balance disorder will cause difficulty in fusion, and both eyes will be unstable and visual fatigue symptoms will occur; when the fusion function is seriously lacking, any tendency to skew will Immediately becomes strabismus, when there is a lack of fusion due to blindness of one eye, there will be different skew at different ages. Of course, there are certain individual differences. Usually, exotropia will appear blindly at birth or shortly after birth; In the case of infants or early childhood, esotropia occurs in a blind eye; if there is an internal or external strabismus between the child and the middle-aged blind, the eye is often maintained in a positive position within a few years and eventually is exotropia; The vast majority of blindness in the year will inevitably lead to exotropia. This difference is largely due to the difference in fusion reflection. In the absence of fusion at birth, the eye is in a physiological rest (abduction). After blindness in childhood, the blind fusion is determined by the rich fusion reflection. This is because the instinct needs to be in the process of gathering. The eyes affect each other regardless of the blind eye, and the gradual decrease of the fusion reflection with age, especially the reduction of the use of the collection after the presbyopia makes the eye position favorable for abduction.
The etiology and pathogenesis of occult is complicated. A kind of slanting can be caused by many factors. Static and dynamic factors can exist at the same time. Neurological factors sometimes exist. Therefore, slanting is often horizontal and vertical slanting exists at the same time. There are also rotational slanting at the same time, but the clinical symptoms are mostly similar, so it should be examined in detail to confirm the diagnosis and appropriate treatment.
Prevention
Stealth prevention
Prevention methods are different for children of different ages, but the key is to prevent children from seeing things that are close together.
1. Infants: Parents must not hang their favorite toys too close;
2, young children: because they can get toys, parents should always pay attention to avoid him looking at toys at close range;
3, preschool children: should take them outdoor activities, and intentionally guide them to see things in the distance.
4, it is worth noting that: the lights in the cradle, or turn on the lights at night to let the children sleep, these too detailed practices are not conducive to prevent children from strabismus.
Complication
Oblique strabismus complications Complications, headache, nausea and vomiting
Mainly complicated by visual fatigue, the general symptoms of patients are: blurred for a little longer, some can not even write or read, dry eyes, dizziness, nausea and vomiting in severe cases.
Symptom
Symptoms of strabismus Common symptoms XV-phenomenon XA-phenomenon strabismus eye pain vertigo nausea
Light asymptomatic, severe due to eye muscle fatigue, headache, eye pain, heavy eyelids, blurred vision, and even temporary diplopia and dizziness, nausea and other symptoms, but after a little rest, the symptoms can disappear.
Examine
Cryptic strabismus
The cover method can be used, the Maddox rod method is checked, and the hidden inclinometer test is more accurate.
Diagnosis
Diagnostic diagnosis
diagnosis:
Diagnosis can be performed based on clinical manifestations and examinations.
Differential diagnosis:
To be associated with paralytic strabismus, common strabismus, and congenital sternocleidomastoid muscle fibrosis.
