Common strabismus

Introduction to common strabismus Common strabismus (comitantstrabismus) refers to the occlusion of the eye movement, the strabismus angle does not change with the gaze eye and the gaze direction, also known as co-rotation strabismus. Common strabismus is more common in early childhood, which is the critical period of visual development. The occurrence of strabismus not only hinders the appearance, but more importantly, seriously affects the visual development of young children. These visual dysfunctions not only bring life and work inconvenience to the patient, but also cause serious trauma in the mind. Therefore, it should be discovered as soon as possible and treated promptly. Some people think that strabismus has no major obstacles, and then healed after growing up, or that the view and viewpoint of strabismus self-healing is wrong as the child grows older. basic knowledge The proportion of illness: 0.004% Susceptible people: good for children Mode of infection: non-infectious Complications: amblyopia, dizziness

Common strabismus cause

(1) Causes of the disease:

The etiology of common strabismus is not yet fully understood. The factors that form common strabismus are multifaceted. For a strabismus patient, it may also be the result of several factors.

The causes of the disease are different. Although each has a certain theoretical basis, there is no theory that can explain all common strabismus problems.

1. Regulating theory: The regulating effect of the eye is related to the collective action of the eye. A certain adjustment brings about a corresponding set. Often, due to the regulation-collective reflex, the effect of the rectus muscle exceeds the tendency of the lateral rectus muscle. And the formation of common esotropia, myopia sees the target with little or no adjustment, the collection force is simultaneously weakened, so the tension of the inner rectus muscle is reduced, and sometimes the common exotropia is formed. In recent years, many facts prove AC/A ( The modulating set/adjustment, that is, the ratio of the triangular prism diopter caused by each diopter adjustment - the triangular prism / diopter ratio, is closely related to the eye position deflection.

2, binocular reflexology: binocular monocular is a conditioned reflex, is to rely on the fusion function to complete, is acquired, if the visual acuity of the two eyes is different during the formation of this conditional reflex, the visual acuity of the eye is subject to obvious sensation or movement disorder ( Such as monocular high refractive error, monocular refractive interstitial, fundus or optic nerve lesions, etc.) hinder the function of binocular single vision, it will produce a state of separation of the eye position, that is, strabismus.

3, anatomy: a certain extraocular muscle development or hypoplasia, abnormal extraocular muscle attachment points, the development of eyelids, abnormal fascia structure, etc., can lead to muscle imbalance and strabismus, such as internal oblique Caused by excessive development of the medial rectus muscle or dysplasia of the lateral rectus muscle or both.

4, genetic theory: clinically common in the same family, many people suffer from common strabismus, the statistics in the literature are not the same, some reported that up to 50% of patients have a familial tendency, there are reports only 10% up and down These facts make people think that strabismus may be related to genetic factors.

(two) pathogenesis

1. Anatomical factors: abnormal development of extraocular muscle congenital, abnormal position of extraocular muscle attachment, abnormal muscle sheath, abnormal development of eyeball fascia and orbital dysplasia, etc., may cause imbalance of extraocular muscle strength, which in turn leads to abnormal eye position. Because this abnormality is very slight, the muscles have undergone adjustment and compensatory changes over time, and gradually manifest as common strabismus. When people in the country measure the extraocular muscle attachment position of patients with common strabismus, they find that the patient has internal fixation. The muscle is more close to the limbus than the rectus muscle of the patient with exotropia, and the attachment position of the lateral rectus muscle is farther away from the limbus. The greater the internal inclination, the closer the position of the medial rectus is to the limbus, the patient with exotropia The attachment position of the medial rectus muscle is far from the limbus, and the greater the external oblique angle, the farther the position of the medial rectus muscle is from the limbus, indicating that the position of the inner and outer rectus muscles is closely related to the occurrence of internal and external strabismus. Scobee A study of horizontal muscle dysplasia found that 90% of strabismus occurring before the age of 6 may have anatomic abnormalities.

2, adjustment factors: when the near object, the lens increases the curvature, thereby enhancing the refractive power of the eye, this function to change the refractive power of the eyes for the purpose of seeing the close distance target, while the adjustment occurs, the eyes rotate internally to ensure The object is imaged in the fovea of the two eyes. This phenomenon is called convergence. The adjustment has a synergistic relationship with the convergence. The larger the adjustment, the larger the convergence, but in the patient with refractive error, the coordination and the convergence are lost. Relationship, and the more serious the refractive error, the more unbalanced the two, the patients with farsightedness (especially moderate hyperopia), the people who have been working closely for a long time, and the people with early presbyopia, because of the need to strengthen the adjustment, the corresponding Excessive convulsions, excessive convulsions may lead to esotropia, people with myopia, because there is no need or little need to adjust, there will be insufficient convergence, which may lead to exotropia, Parks found that 57% of the acquired internal slant has adjustment The proportion of the convergence is unbalanced, and the external oblique 59% has an imbalance between the adjustment and the convergence.

Common strabismus prevention

Prevention of children's strabismus focuses on eliminating the conditions that cause strabismus. Try not to keep children away from objects in close range and in the same direction. If you find that your child has strabismus at 2 months, try the following simple method: if it is internal oblique, parents can Talk to your child at a remote location, or hang some colorful toys in a distance that is far away, and let the children see more things that move.

Common strabismus complications Complications, amblyopia, dizziness

The most common complication is strabismic amblyopia, which refers to the absence of organic lesions in the eyeball and the inability to correct visual function due to eye deflection.

After the eye position is skewed, the visual center actively suppresses the visual function of the oblique eye. The result of the inhibition causes the development of the macular function to be stagnant, forming amblyopia, and some do not produce inhibition, but form anoretical retinal correspondence (ARC). The macula has a new correspondence with the retinal components outside the macula. The visual function of the retinal components other than the macula is low. The corresponding results of retinal abnormalities also form amblyopia, especially in infants and young children, due to retinal vision. The central function is not fully developed, that is, the inhibition and abnormal retinal correspondence are generated, which is more likely to lead to the formation of amblyopia. Even if these children with strabismus have refractive errors, they cannot improve their vision through the glasses. The severity of amblyopia and the age of onset of strabismus , duration, treatment, morning and evening and other factors are closely related, congenital strabismus, monocular strabismus, long-lasting and untreated strabismus, easy to form severe amblyopia, clinically seen patients with severe amblyopia, mostly due to strabismus or squinting Due to the paradox, some parents think that strabismus does not affect The child's whole body development only affects the appearance. Some doctors even think that strabismus should be corrected after the adult. These views are all wrong. It ignores the consequences of strabismus which can cause amblyopia, and the patient misses the treatment of amblyopia. Good timing, even if the treatment of amblyopia after adult is effective, it is very difficult, especially for severe amblyopia in one eye. After covering the healthy eye, the patient can not work and learn normally. It is difficult to adhere to the treatment. Therefore, the early stage of strabismic amblyopia should be emphasized. The importance of treatment to prevent the occurrence of amblyopia, can cause recurrence, eye dizziness, affecting normal work and life.

Common strabismus symptoms common symptoms diplopia nystagmus strabismus amblyopia cross gaze squinting inhibition palpe strabismus

Eye position deflection

The deviation of eye position means that the two eyes cannot simultaneously gaze at the same target, and the visual axes of the two eyes are separated. One eye looks at the target and the other eye deviates from the target.

The oblique direction of the common strabismus is more common with horizontal deviation. Simple vertical deviation is rare, and some can be combined with vertical deflection. If some patients with internal obliqueity appear upward when the eyeball rotates, this vertical The deviation is not entirely due to extraocular muscle paralysis, but often because the inferior oblique muscle is thicker than the upper oblique muscle and the strength is too strong. When the eyeball is turned inside, the lower oblique muscle strength is stronger than the upper oblique muscle and the eyeball is turned up. Caused.

The deviation of the eye position of the common strabismus may be monocular, that is, the eye position deflection is often fixed on one eye, or may be alternated between the eyes, that is, sometimes the right eye is skewed, the left eye is gaze; sometimes the left eye is skewed, The right eye is watching, but the eyes cannot look at the same target at the same time.

Usually, the oblique angle of the oblique eye when the eye is gazing at the target is referred to as the first oblique angle; while the oblique eye is focused on the target, the oblique angle of the healthy eye is referred to as the second oblique angle, and the first oblique angle of the common oblique is equal to the second oblique angle Perspective, this is different from non-common squint.

Because of the common strabismus, the extraocular muscles and the nerves that control the movement of the eyeball have no obvious damage, so there is no obvious obstacle in the eye movement. When the eyeball is gazing at all directions, the degree of deviation of the eye position is about the same, and when any eye is used as the gaze eye, The deviation of the other eye is almost the same, but in patients with AV strabismus and patients with secondary common strabismus, the mild strength of one extraocular muscle may be enhanced or weakened. For example, patients with internal obliqueity may show mildness. Insufficient rotation and internal rotation enhancement, the AV squint upward gaze and the downward gaze have a significant difference in horizontal skewness, which is mainly due to excessive or insufficient muscle strength in the horizontal or vertical.

Looking at the target at a glance, the other eye is skewed, that is, when gazing with the left eye, the inclination is concentrated on the right eye; when the right eye is gazing, the inclination is concentrated on the left eye, and the inclination is the same, that is, Looking at the target with a healthy eye, the skew angle of the squint eye (the first oblique angle of view) is equal to the squint eye, and the angle of the healthy eye (the second oblique angle).

The eye movement is unobstructed, and the degree of deflection of the two eyes remains the same when rotated in all directions. However, under the influence of some high-level neurological activities, such as when sleeping, anesthesia or using a set of adjustments, the slope may have The difference is that patients have no self-conscious symptoms and often seek medical treatment because of their appearance.

classification:

(1) According to the nature of skew, it can be divided into:

Monocular strabismus: often fixed with one eye to look at the target while the other eye is skewed, and the oblique eye has significantly decreased vision;

Alternate strabismus: Both eyes can rotate or gaze, if the left eye is gazing, the right eye is skewed, and the right eye is slanting, the left eye is skewed, and the two eyes are often close to each other.

(2) According to the direction of deflection, it can be divided into:

Esotropia eyeball is biased inward;

Exotropia eyeballs are outward;

Hypersoropia eyeball is upward;

Hypotropia eyeballs are downwards.

2. Double vision and confusion

Diplopia is a phenomenon in which two eyes treat the same object as two objects. Since the eye position is skewed, the correspondence between the retinas of the eyes changes, that is, the relationship between the original healthy macula and the oblique macula. It becomes a healthy eye macular corresponding to the retinal component outside the erythema maclot. When the same object image falls on the non-corresponding point of the retina of the two eyes, it is perceived by the visual center as two object images, and the healthy eye is the macular gaze, and the resulting image is clear. Located in front of the body, it is called a real image; the squint is gazing at a point outside the macula, and the resulting image is blurred, which is called a virtual image.

The direction of strabismus in common strabismus is more common in horizontal, so double vision is also the most horizontal. In the oblique direction, the external image falls on the retina of the healthy macula and the nasal side of the erythema, and the visual direction of the healthy macula is still projected. In front of the front, the visual direction of the retinal component on the nasal side of the squinted macula is cast to the temporal side, so the internal oblique produces ipsilateral diplopia. When the external oblique is present, the external image falls on the retina of the healthy macular and the macula of the oblique eye. The retinal component of the temporal side is projected to the nasal side, so the external oblique produces cross-division.

Confusion is the result that the image of different objects on the outside falls on the corresponding points of the retina of the two eyes. After the eye position is deflected, the visual direction of the main points corresponding to the yellow spots of the eyes is separated and no longer cast to the same place or the same Direction, however, the center has not yet had time to adapt and deal with this change, the healthy macula still accepts or perceives the object image in front, while the squinted macula accepts or perceives the object image in another orientation, the images of two different targets are coincident , it creates visual confusion.

Diplopia and confusion occur in the early stage of strabismus, but because of the common onset of strabismus, it often occurs in early childhood. At this time, vision is at the development stage, binocular vision has not been firmly established, and visual disturbances of diplopia and confusion are soon It has been eliminated by a series of adjustments and compensations of the entire visual system, and children can not express the symptoms of these visual disorders in words. Therefore, there is often no double-viewing, only the older ones in which binocular vision has been firmly established. Children, when acute common strabismus suddenly occurs, will complain of double vision, but the double vision of common strabismus is different from the non-common strabismus. The double vision distance of common strabismus does not change with the direction of gaze and the change of gaze And change, that is, whether you look at it in any direction, or look at it with either eye, the complex distances of the common strabismus are roughly equal, and the relationship of the complex images is consistent, and the complex distance is only the target of the fixation. It is related to the distance.

3. Squinting inhibition

The inhibition of deviating eye is caused by diplopia and confusion after the eye position is deflected. In order to avoid the interference of these visual disturbances, the visual center actively suppresses the reaction of producing the squint eye object, and there are three ways to suppress it. Immobility inhibition, mobility inhibition and non-central gaze, fixed inhibition is inhibition of fixation occurring in strabismus, inhibition not only occurs when the strabismus is skewed, but also when the squint is in the gaze position, long-term fixation inhibition The result is inevitably leading to a decrease in the function of the macula in the eye, that is, the so-called inhibitory amblyopia. The earlier the strabismus is, the longer the duration, the deeper the inhibition, and the more severe the amblyopia. This inhibition occurs mostly in the constant monocular strabismus. Patient.

The inhibition of mobility means that the inhibition occurs only when the eye position is skewed. When the squint eye turns into the gaze eye, the inhibition disappears, the eyes are alternately skewed, and the eyes are alternately gazing. Since the two eyes can be used alternately, the inhibition does not occur. Sexual amblyopia, each eye can maintain normal central vision, but the eyes can not simultaneously gaze at the same target, so there is no more binocular vision or no normal binocular vision. This form of inhibition often occurs in patients with alternating strabismus.

Non-central gaze is also known as eccentric fixation. The mechanism of non-central gaze formation is due to the deepening of monocular inhibition. The function of the fovea is extremely low, even lower than around the macula, and the gaze center is moved to the area around the macula. At this time, when both eyes are viewed at the same time, the oblique eye cannot be used to focus on the fovea. When the eye is blocked and the strabismus is forced to gaze, the oblique eye cannot be gaze at the fovea of the macula, but is gaze outside the fovea of the macula. Non-central gaze, the result of such inhibition often forms severe amblyopia.

4. Single eye

After monocular fixation, that is, after the eye position is deflected, the visual function of the strabismus eye is suppressed. The patient always looks at the object with one eye, and the eyes cannot simultaneously look at the object at the same time. There is no chance of coordination and coordination, such as early onset, it is inevitable. Influencing the development of binocular vision, some patients can have no binocular vision at all. If you use the same machine to check, you can only see the picture of one side of the lens tube. You can not see the picture of the lens on both sides at the same time, even if you can see it at the same time. Two pictures, but not two pictures can be overlapped together. Some patients can have simultaneous visual function or fusion function, and even have certain stereoscopic vision, but these binocular visions cannot be normal binocular vision, if using the same vision When the machine is inspected, the position of the coincidence point is not in the normal range, the intrinsic angles tend to coincide in the range of excessive collection; the external obliques tend to overlap in the excessively separated range, the fusion range is often reduced, and the stereoscopic sharpness is often too large. (400 seconds), some authors reported that in 238 patients with amblyopia, 95 patients had no binocular vision, of which 78 patients had strabismic amblyopia without eyes, after treatment, 58.9% of amblyopia Twenty-four cases were established without stereoscopic vision, all of which were patients with strabismic amblyopia, and some authors reported that in 19 patients with strabismus with normal binocular vision, stereopsis (stereoscopic sharpness 400 sec) 1 person, 13 people with stereo blindness, accounting for 68.4%, it can be seen that strabismus is extremely harmful to the establishment and development of binocular vision, and the younger the age of strabismus, the longer the duration, the greater the influence on the establishment of stereoscopic vision, especially 2 Pre-year-old patients have a worse prognosis. Therefore, strabismus should be corrected as soon as possible to create opportunities for simultaneous use of both eyes to promote the establishment and consolidation of binocular vision.

5. Cross gaze

Children with obvious internal oblique, especially those with congenital esotropia, can look at each other while looking straight ahead, while looking at the side, use the right eye to look at the target in the left field of view and the left eye to the right. The target of the lateral field of view, this phenomenon is called cross fixation. Because the eyeball does not need to be turned outward when looking at the side, the function of the external rotation is suppressed, and the appearance is similar to that of the external rectus muscle paralysis. The true external rectus paralysis, if covered for a few hours, the external rotation function returns to normal, or the child's head suddenly and quickly turned to the opposite side, you can see the normal eye movement of the eye (doll headphenomenon).

6. Binocular vision change

The field of view is the spatial range seen when the eyeball is gazing straight ahead. The part of the eye that overlaps each other is called the binocular field of view. This is the basis for the formation of binocular vision. The part of the binocular vision that does not overlap is on the temporal side. On the side of the new moon, the new moon on the side can only be seen by the same side.

After the eye position is skewed, the visual field of both eyes changes. When the internal oblique is oblique, the oblique eye field shifts to the nasal side, so that the overlapping fields of the eyes expand, the range of the temporal field decreases, the total visual field narrows, and the oblique eye gaze range When shifting to the temporal side, the field of view of the oblique eye increases, and the total field of view of both eyes is enlarged, but the field of view in which the eyes overlap each other is reduced.

In the case of esotropia, cross-gaze may occur; in the case of external strabismus, ipsilateral gaze may occur, and in the case of external strabismus correction surgery, multiple external rectus muscle ablation may be performed, postoperative eye position correction, and the temporal field of the temporal field may be reduced.

7. Ipsilateral gaze

According to the patient's typical clinical manifestations, it is not difficult to diagnose. The choice of common strabismus treatment methods is closely related to detailed eye examinations, especially for infants and young children who cannot report their medical history and cannot cooperate with the examination. Patience, meticulously, repeated examinations in order to grasp the various materials related to strabismus, and correctly formulate treatment plans. The examination contents mainly include the following items:

(1). The situation of the child at birth: whether it is a full-term delivery, with or without oxygen and midwifery, because midwifery and oxygen can cause retinal hemorrhage and vitreous lesions, causing perceptual strabismus.

(2) Whether there is abnormal performance when viewing objects in normal times: if the distance of the object is too close, the object is hoe, the eye is blinking, and one eye is closed under strong light.

(3) Time of occurrence of strabismus: The age of onset is closely related to the prognosis. The earlier the strabismus occurs, the worse the treatment effect is. The congenital strabismus occurred before the age of half is difficult to obtain functional cure. The onset time of some patients is difficult to be certain. Parents think that the child's eyes are oblique, but the actual is not necessarily true strabismus; some strabismus is discovered by others, such as neighbors, relatives, teachers, etc. Parents do not know, should refer to the photos of childhood to help diagnose.

(4) Onset of the disease: The deviation of the eye position at the time of onset is intermittent or constant. If it is intermittent, it occurs under what circumstances, whether there is obvious law, and when it changes to constant strabismus.

(5) strabismus nature and skew direction: that is, oblique or oblique, internal oblique or external oblique, vertical strabismus or alternating upper strabismus.

(6) Eyes: It is a constant strabismus or bilateral strabismus, and a constant strabismus is prone to severe amblyopia.

(7) Rapid onset: gradually occurs or suddenly occurs after birth.

(8) Accompanying symptoms: whether there is double vision, the nature and characteristics of double vision, whether there is nystagmus and recessive nystagmus, and whether vertical skew is combined.

(9) Inducement: Whether there are induced factors such as fright, high fever and trauma.

(10) Treatment: Whether to perform refractive correction, amblyopia training, surgical treatment and surgery time, eye, surgery.

(11) Family history: Among the family members, the ancestors or the same generation have the same disease.

Common strabismus examination

No special laboratory inspection methods.

1. General eye examination

Including the examination of far, near vision and corrected vision as well as extraocular, refractive interstitial and fundus examinations, in order to understand whether there is amblyopia, whether there is obvious refractive error, whether there are other eye diseases causing strabismus, with or without pseudo strabismus, etc. .

(1) Vision examination: should check far, near vision and corrective vision, children's visual examination is affected by many factors, such as children's age, intelligence, understanding, expression, mental state and environmental conditions, etc., especially infants and young children Can not cooperate well, vision examination is quite difficult, and there is no simple and accurate, accurate and reliable inspection method, so it should be patiently and meticulously repeated inspections, attitudes are amiable, methods are flexible, try to get children to cooperate, for Avoid infants and children crying and crying, the examination is not necessarily in the diagnosis room, the child can be placed in the waiting room, let him play with toys at random, read the book, observe whether the performance of the object is abnormal, or use toys and variable The brightness of the light is done to check the target to attract the child's interest and strive for the child's cooperation.

Inspection method: Usually children over the age of 3 can use the "E" shape chart or other letter eye chart check. The training should be carried out first, and the children should cooperate for the analysis. The results of several tests should be comprehensively analyzed. The following methods are commonly used for visual inspection of infants under 3 years of age.

1 eye and head following movement: observing the ability of infants to fix and follow the target is the main method to judge the visual function of the baby. If the appropriate visual target is used, it can confirm that most newborns have fixation ability, the most ideal visual target. It is a human face, especially the face of a baby mother. When the baby is lifted upright during the examination, the examiner slowly moves his face to observe whether the baby moves with it. The movement of the baby following the target is rough. Do not turn the baby while checking. Because this can cause vestibular-eye reflexes, does not indicate visual function, 3 months of babies can have a red spherical optotype in the front of the eye, the size of the optotype is different, the observation optotype is horizontal in the field of view, vertical movement The baby's follow-up of the optotype, estimating the baby's vision.

2 disgusting reflex test: This test is used to judge whether there are amblyopia or binocular vision in infants of large age. When the child is examined, the child is sitting on the mother's leg, and the cornea is illuminated by light. The eyes are repeatedly covered and observed, and the head is shaking, crying, and face. Changes, such as when covering one eye, the above situation, it means that the eyesight of the eye is good, the eyesight of the eye is not covered, and the visual target is not visible.

3 squint eye gaze ability check: use the light to illuminate the cornea, if the eyes can stabilize the gaze, and the reflective point is in the center of the cornea, it means that the eyes are mostly centered, and the visual function is good. If the light or target is not stable, even the eyeball appears. Tremor, indicating that the visual function is low.

4 optokinetic nystagmus (OKN): During the examination, a test drum (striped drum) with black and white vertical stripes is placed in front of the baby's eyes. At first, the baby's eyeball follows the movement and will be generated later. Rapid corrective reverse motion, this repeated alternating forward and reverse eye movements, forming optokinetic nystagmus, gradually narrowing the strips of the test drum, and producing the narrowest stripe of visual nystagmus The baby's vision, the neonatal visual acuity measured by this method is 20/400, and the visual acuity of the infant for 5 months is 20/100. At present, some countries have adopted the visual tonometry method as a routine method for detecting children's vision.

5Preferential looking (PL): Since a baby's fixation is more interesting than a solid gray target stimulus, the baby looks at the two visual targets, one with black and white stripes. One is a uniform gray optotype, and the baby selectively looks at the black and white stripes. When the two optotypes appear at the same time in front of the baby, the examiner pays attention to observe the optotype that the baby is willing to watch, and replaces the stripe width until the baby is unwilling to continue observing. Up to now, the width of the stripe represents the PL vision of the baby, and can also be converted into a certain Snellen visual acuity.

6 visual evoked potential (VEP): after the eye is stimulated by light or pattern, the electrocortical changes can be produced in the visual cortex. The changes are processed and recorded as visual evoked potentials. VEP represents the third from the retina. Neurons, ie, ganglion cells above the visual information transmission, different size of the visual target induces different potential responses, as the square shrinks and the narrowing of the grid, the VEP also gradually changes, continuously reducing the size of the target until When the VEP is no longer changed, the highest visual acuity of the subject is calculated according to the width of the square or the grid that can cause the change. The VEP examination is superior to other children who do not speak, and the stimulation condition is stable. In the case, it is a more objective and accurate method of examination, but the equipment is expensive and difficult to master. The visual acuity of the baby is measured by VEP. It is found that the first 8 weeks after the birth, the progress is very fast, and the visual acuity of 20 to 20 months has been reached. .

7-point eyesight chart: This eye chart is to arrange 9 black dots of different sizes on a milky white disc for the child to identify. The eye chart is 25cm away from the eye until the child can't distinguish it. It is used to check the child's near vision. The test result can be converted into an international near vision chart as shown in Table 1.

8 Children's image chart: It is designed to be children's interest and easy to express with various patterns familiar to children.

9E word chart: The results of multiple examinations can be used to evaluate the visual function of children.

In short, the development of visual function in children will take some time to mature after birth. The visual acuity varies with age. In the same age group, the visual acuity is not the same. Generally speaking, the visual acuity increases with age. The degree gradually increased. It was reported that 95% of 2.5-year-old visual acuity was 0.5-0.6, 61.3% of 3-year-old naked-eye vision was 1.03%, 73.6% at 4 years old, 80.4% at 5 years old, and 95.6% at 6 years old.

In China, authors used visual acuity to measure the visual acuity of 43 normal infants aged 4 to 28 weeks. The results were as follows: about 0.012 for 4-8 weeks, 0.025 for 9-12 weeks, and 0.033 for 13-16 weeks. ~20 weeks is about 0.05, 21 to 24 weeks is about 0.1. Some people in foreign countries measure the visual acuity of children aged 1 to 5 years. The results are: 20/200 for 1 year old, 20/40 for 2 years old, and 20/3 for 3 years old. 30/25 at 30 and 4 years old and 20/20 at 5 years old.

(2) Examination of fundus and refractive interstitial: exclusion of fundus diseases and refractive interstitial opacity, such as retinoblastoma, post-crystal fibroproliferative disease, Coats disease, etc. Secondary strabismus caused by poor vision, clinically Many children have strabismus to the hospital for treatment. After detailed examination, it is found that there are obvious abnormal changes in the posterior segment of the eye. For patients with such strabismus, the diagnosis should be made first, and the primary disease should be treated. If the condition is stable, then consider whether to perform strabismus surgery. .

2. The squint nature and the squint direction check: the commonly used occlusion method is used for inspection. The occlusion test method is a simple and convenient method, and the result is accurate and reliable. The nature and direction of the eye position deflection can be quickly determined, and different gaze positions can be determined. When the eyeball is deflected, the fixation state of the strabismus is judged, and the eye movement is found to be abnormal. The type and characteristics of the double vision are determined. If the prism is added, the accuracy of the strabismus can be determined, and the cover is covered by the double eye and the cover is covered. Monocular cover, except for cover inspection.

(1) Alternate occlusion method: This method is a method for checking the presence or absence of occult and intermittent strabismus. When the patient is seated with the examiner during the examination, the two eyes are at the same height, and the patient is allowed to look at the light or small visual target at 33 cm or 5 m. Use an opaque hard plate with a width of 5cm and a length of 10~15cm as the eye-blocking plate, and cover the eyes alternately. Observe whether the eyeball rotates or rotates when the cover is removed. If the eyeball does not rotate, it means that both eyes are covered and uncovered. Can coordinate the gaze, the eye position is not skewed, if the eyeball rotates, it means that the occlusion eye deviates from the normal gaze position, no longer gaze at the target, and the fusion function is restored when the occlusion is removed, the eye returns to the gaze position, and the eyeball is inward. Rotate to the external oblique, outward to the inner oblique, downward to the upper oblique, upward to the lower oblique, if not covered, both eyes are looking at the eye position, when the eye is covered, the eye position is skewed, remove When the cover is closed, the positive position cannot be restored, so that the patient can look at the close target, the fusion function of both eyes is restored, and the oblique eye is turned into the positive position, which is explained as intermittent strabismus. The basic principle of the method is to eliminate the fusion function by covering the eyes and make the eyes Become a monovision, must be quickly converted blindfold plate check, do not let your eyes have the opportunity to expose the same time, the time should be covered in more than 2s, repeatedly, completely destroyed integration, fully exposed to the eye position deviation degree.

(2) Monocular covering and de-covering inspection method: This method covers one eye and observes the rotation of the uncovered eye. When the covering is removed, the movement of both eyes is observed to judge the nature and direction of the strabismus.

1 In the case of binocular gaze, the eyeball does not rotate when covering any eye and removing the cover, indicating that after the fusion is destroyed, the macula gaze can be maintained, and the visual axes of both eyes are kept parallel and there is no strabismus.

2 No matter whether one eye is covered or not, the eyeball rotates in the uncovered eye, indicating that the naked eye has an eye position skew, and the eye is not able to look at the target. After the eye is covered, the naked eye is forced to change from the oblique position to the gaze position.

3 When the cover is removed, the eyes do not rotate. There may be two kinds of situations. One is the right eye and the other is the alternating strabismus. Both eyes have good vision and have gaze function. In patients with alternating strabismus, the eyes cannot At the same time, when gazing, when the eye is covered, the naked eye is gazing. When the cover is removed, the naked eye is still watching the eye position, and the original covered eye is still in the oblique position.

4 When the cover is removed, if both eyes rotate, it means that the naked eye is a constant squint eye, and the covered eye is a gaze eye, because when the eye is covered, the naked eye, that is, the constant squint eye, is forced to turn into a positive position and gaze. The target is that when the eye is covered, the eye is rotated and becomes a squint. However, when the eye is covered, since the eye is the eye, it immediately turns back to the positive position, and the other eye rotates accordingly. The original oblique position, so when the single eye is constantly deflected, both eyes appear to rotate when the eye is covered and uncovered.

5 When covering the cover, if the original naked eye does not move, and the cover eye rotates, it means that it is hidden, the covered eye is covered, the fusion is broken and the deflection occurs. When the cover is covered, the fusion is restored, and the covered eye turns into the eye position. .

6 Cover any eye, when the eye is covered, the eyeball rotates from top to bottom, accompanied by the rotation of the eyeball, indicating that the eyes are alternately inclined, so-called vertical eye position separation.

In addition, the clinical use of the occlusion test can also distinguish the strabismus with cross-gaze as common strabismus or paralytic strabismus, determine the nature of gaze, diagnose intermittent strabismus, etc., cover the gaze for several hours, if the abduction function is restored, then cross Common slanting or pseudo-external palsy of gaze. If the gaze is gaze and the strabismus is gazing, the strabismus cannot be turned to the right position. The corneal gliding point is not in the center of the cornea, or nystagmus occurs, indicating that the squint is the side center. Gaze, if the eye position is right when the close-up examination, after cloaking, the occultation of the covered eye appears, and the squint after occlusion, indicating intermittent strabismus.

3. Eye movement check

Through the examination of eye movements, to understand the strength of muscle strength, whether there is obvious muscle paralysis or excessive muscle strength, whether the movement of both eyes is consistent, when examining eye movements, the examination of monocular movement and binocular movement should be performed separately.

(1) Monocular exercise:

1 When the internal rotation of the pupil reaches the upper and lower puncture points, the inner rotation is stronger than the limit, and the inability to reach is insufficient.

2 The outer edge of the cornea reaches the external ankle angle when the external rotation is exceeded. If the limit exceeds this limit, the external rotation is too strong, and those who cannot reach the outside are insufficient. It is necessary to pay attention to the difference between true abduction paralysis or pseudo abduction paralysis. In addition to the method of checking the abduction function after a few hours of covering, the "doll head test" can also be used, that is, the head of the child is hand-held, and the head is forced to suddenly turn to the opposite side while observing Whether the eyeball can be turned outwards, if it can be transferred to the external ankle angle, it is a false abduction paralysis. If it cannot be rotated, it is a true abduction paralysis.

3 When the car is turned up, the lower edge of the cornea reaches the inside and the outer iliac crest is connected.

When the 4 turns down, the upper edge of the cornea reaches the inside and the outer rim is connected.

(2) Binocular movement examination: Both eyes include two-eye movement and two-way movement, and the two-eye movement is coordinated under normal conditions. If there is eye muscle paralysis or sputum, the two-eye movement can show different degrees. An abnormality, which can be judged by comparing the amplitude of the eye movement of the terminal eye position with the degree of eyeball deflection when gazing in different directions. When the eyes move in the same direction in one direction, the eye does not reach the proper position or The tremor-like movement (which should exclude the physiological nystagmus that occurs when the eye turns to the extreme side under normal conditions) indicates that the muscles rotating in this direction are insufficiently functional. If the movement exceeds the normal range, it indicates the muscle function of the movement in that direction. Too strong, if moving in all directions, the eyeball skewness is equal, it is common strabismus, otherwise it is non-common strabismus.

The coordination state of the binocular movement can also be checked by the covering method. The eye mask is used to cover one eye line of sight, and the other eye is gazing in all directions. The patient can only look at the target with one eye, and the examiner can observe the relative positions of the two eyes at the same time. For example, when the patient is looking to the upper right, the eye mask is placed on the right side of the patient. At this time, the patient can only focus on the target with the left eye, and then the eye mask is placed in the center of both eyes. At this time, the patient can only use the right eye. Looking at the target, if the patient has abnormalities in the extraocular muscles, this can be clearly manifested.

In the two-eye co-movement, the two conjugated active muscles are called the same-directional mating muscles. There are 6 groups, namely the left intraocular rectus and the right lateral rectus muscle, the left external rectus and the right intraocular rectus, left. The right rectus muscle and the right lower eye oblique muscle, the left lower inferior rectus and the right superior oblique muscle, the right upper rectus and the left inferior oblique muscle, the right lower rectus and the left superior oblique muscle, the six pairs of the same direction The orientation of the same direction, that is, the position of the eyeball that is commonly used in clinical examination to compare and compare the muscle function of the partner, is called the diagnosis of the eye position.

The anisotropic movement includes three kinds of horizontal anisotropic movement, vertical anisotropic movement and rotational anisotropic movement. The spouse muscle of the anisotropic movement is the convergent movement of the rectus muscles of the two eyes, and the lateral rectus muscles of the two eyes are separately moved, and the two eyes are up and down. The rectus muscles were moved vertically, the superior oblique muscles of both eyes were subjected to internal rotation, and the lower oblique muscles of both eyes were externally rotated.

In daily activities, the most used anisotropic movements are horizontal anisotropic movements, and the most common use of convergent movements. Therefore, in the clinical examination of extraocular muscles, the examination of the function of convergence is quite important.

Convergence is an indispensable function of anisotropic movement in binocular vision. It can be divided into two types: autonomous convergence and non-autonomous convergence. Non-autonomous convergence is divided into tension conduit, fusion convergence, regulatory convergence and near-inductive convergence. Regulatory convergent and convergent convergent are the main convergent components, and the adjustment is similar. Convergence must also maintain sufficient reserves for long-term work without fatigue. In order to work comfortably at close range, only 1/3 can be used frequently.1/333cm48-4 80 4

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