Shortsighted

Introduction to myopia Myopia is also called short-sightedness because it can only be seen and the distance is far from clear. When in a resting state, parallel light from infinity, after being refraction through the refractive system of the eye, gathers in focus before the retina and forms an unclear image on the retina. People with myopia can limit the incidence of light by squinting their eyes, thus reducing the aberrations so that they can see more clearly. Myopia originally meant to squint. The distance vision after myopia can be corrected by a concave lens. The degree of refractive error is usually measured by diopter. 0 to -3.00D is mild myopia, -3.00 to -6.00D is moderate myopia, and higher than -6.00D. It is high myopia. People with high myopia are at high risk of some eye diseases, such as retinal detachment, because the eye axis is too long. basic knowledge The proportion of illness: 1.2% (this disease is a common disease in adolescents, the incidence rate is above 85%) Susceptible people: no special people Mode of infection: non-infectious Complications: retinal detachment malnutrition anisometropia amblyopia strabismus open angle glaucoma

Cause of myopia

First, the cause of the disease:

Hereditary factor (35%):

According to the group survey, the incidence of myopia among ethnic groups has been very different. Among Asians, Chinese and Japanese have more myopia, and European Jews are more common than natives in Germany and Germany. Stephoson In 1919, the eyesight of children in London was investigated. Jewish children have about 10 times more myopia than local children.

1, high myopia: Hu Ningning and other surveys of 61 families found:

(1) Both parents have high myopia, and 12 offspring are highly myopic (100%);

(2) One of the parents has high myopia, and the offspring is also sick (indicating that the other of the parents is heterozygous), 23 of the 40 children are highly myopic (57.5%), and the expected incidence (50%) Compared, P>0.05;

(3) The parents showed normal behavior, and 25 families with offspring (indicating that both parents were heterozygous), 68 out of 197 children, after the use of Winburg and Lenz correction, the incidence rate was 21.3% and 22.2%, compared with the expected 25%, P>0.05, all of which are consistent with the autosomal recessive inheritance law, but can be affected by environmental factors to reduce the degree of manifestation or incomplete, high myopia, such as Marriage with normal phenotypes, 18% to 24% of the chance to marry heterozygous people, may give birth to children with high myopia, therefore, it is safer to assume that China's high degree is considered as autosomal recessive inheritance.

2, simple myopia: low, moderate myopia, refers to myopia or myopic astigmatism below 6.0D, generally no obvious fundus changes, corrected visual acuity can be normal, is the most common kind of refractive error, in twins The investigation found that regardless of myopia consensus rate or diopter difference, the same degree of the same egg is greater than the ectopic, statistical treatment has significant significance, and suggests that genetic factors play an important role in the occurrence of myopia, according to this group Coefficient calculation, myopia heritability was 61%, and the twins were determined. The genetic index was 65%. The genetic indices of the axial length, corneal curvature radius and anterior chamber depth were 55.5%, 49.1%, and 72.1%, respectively. The first-degree relatives of high school students surveyed and calculated the heritability of 50.5%, that is, genetics and environment accounted for about half of the occurrence of myopia, so it is inferred that it is simply regarded as multi-factor inheritance.

In summary, high myopia is autosomal recessive; general myopia is multifactorial inheritance, subject to both genetic and environmental factors.

Environmental factor (25%):

Certain environmental factors can increase eye regulation to form a certain degree of refractive myopia, whether it can make the axial lengthening to form axial myopia, there is still doubt, Duke-Elder's ophthalmology textbook has reported that young animals are raised in cages. In recent years, there are examples of increasing myopia in the wild. In recent years, foreign and domestic scholars have placed young animals in artificially designed special visual environments to observe the effects of the environment on eye development. Some achievements have been made, such as Wiesels eyelids of macaques. Stitching, forming upper and lower sacral adhesions, forming a translucent cover film in front of the eyes, feeding in bright places, wherein the 5th monkey is unilateral eyelid suture for 18 months, open suture, and banded light examination after ciliary muscle paralysis The diopter and eye length were measured after eye and eyeball removal. The results showed that the suture eye formed -13.5D myopia, and the anterior and posterior axis length of the eye also increased by 20% (Fig. 1). The 8th monkey was matured and fed for 17 months diopter. There was no change in the eye axis. After the monkey was born, the eyelids were sutured, and in just 6 weeks, it became a 2.75D myopia (Table 1). In 1979, Wiesel et al. fed the eyelid sutured monkeys in the all black environment strip. Under the condition, it was found that myopia did not occur.

It can be seen from the above experiments that the objective condition for the formation of experimental myopia is to add a translucent membrane in front of the eye, which allows part of the light to pass through, but can not be clearly imaged on the retina, thus making it in the process of development. The test animal loses the normal visual stimulation required during the development of the eyeball. The age of the experimental animal, that is, whether the eye is in the growth stage, is also a determining condition for the formation of experimental myopia.

In 1980, Wallman et al. conducted an experimental comparison of the Laiheng chicks according to the two functions of the chicken eye. The A in Figure 2 is to point the eyes to the side (the far side) The line of sight that is seen is hidden, and can only be seen directly in front of the tip of the mouth (seeing the near side); B in Fig. 2 is to cover the line of sight of the right eye and can only look far; C in Figure 2 is The right eye is covered with a translucent membrane and fed for 4 to 7 weeks for refractive examination and axial length measurement. The results of the measured diopter are shown in Figure 3. It can be seen that the normal and restricted lines of sight are only lateral ( Far) viewers, the diopter is similar, limiting the line of sight to the near-looking experimental animals to produce high myopia (mean -10.0D), correspondingly the eye axis of this group is also significantly increased compared to the side viewers, 2 C, covered with transparent film in front of the eyes, also occurred high myopia (mean -12.0D), and this group of eyeballs not only look farther than the normal group and the side, but also significantly increased compared to the closer The author believes that in the development stage of the chicken, it can only be seen close, caused by excessive use adjustment, and conversely, when the experiment is carried out, the lateral side cover of the eye goes. , The subject eye can return to the front, when the cover is removed it depends on the subject animal eye whether mature.

Combining the above experiments, it can be shown that changing the visual environment of young animals can change the eye diopter and the axis of the eye in the developing stage. Wallman's experiment is caused by the excessive observation of the chicken, which is a long-term controversial child close-up. Indirect support is provided by the statement that homework can cause myopia.

Recently, some people in China have used the method of forward-looking research to observe the role of environmental and genetic factors in the pathogenesis of myopia. The subjects were normal pupils with normal vision, and the factors affecting myopia were followed up after two years of follow-up. Analysis and judgment, the results show that in terms of genetic factors, the ratio of the incidence of myopia in children with no myopia and one with myopia or both of them is 1:2.6:3.8; in terms of environmental factors, the reading time after class is The ratio of new incidence of myopia in 1~2h:3h:4~5h is 1:2.1:3.2. Therefore, genetics and environment are two important factors affecting students' myopia. It is believed that the genetic factors cannot be changed at present. In the case of changing the environment is the decisive factor in the prevention of myopia.

Second, the pathogenesis

The pathogenesis of myopia includes the etiology and mechanism of occurrence, which can be discussed separately from simple myopia and pathological myopia.

1, simple myopia

(1) Etiology: There are many hypotheses for simple myopia, which can be summarized into two major categories: genetic and environmental.

1 Genetic Hypothesis: There is obvious family aggregation in simple myopia. In the investigation of students and other people, the parents are all myopic. The incidence of myopia in the offspring is significantly higher than that in the parents. The latter is much higher than the other. Both parents have no nearsightedness, indicating that heredity is one of the important causes of myopia. The incidence of myopia in different races is very different. The incidence of yellow race is the highest, followed by Caucasians and blacks. Even in the same Under environmental conditions, there is still a significant difference in the incidence of myopia in different races, indicating that genetic factors are the main cause of ethnic differences.

2 Environmental Hypothesis: It is considered that simple myopia is determined by environmental factors, mainly near-eye work. Epidemiological investigations have found that the incidence of simple myopia is related to the workload of near-eye. First, there is a lot of near-eye work, then myopia occurs. The former is Because the latter is fruit, nutrition, sports, organophosphorus pesticide pollution and other factors related to the incidence of myopia, remains to be studied.

There are two main types of myopia models caused by environmental factors in animal experiments: one is to limit the animal's visual space to make it look close to the long-term; or to wear a negative-spherical lens to make the object image fall behind the retina, simulating near Environment, can induce myopia, such myopia is close to human myopia, is also the argument for near-myopia, another type of experimental myopia is sutured eyelids or wearing a light-colored white eye mask, deprivation of animal shape, It can also cause myopia, which is called form deprivation myopia. In humans, this condition is extremely rare, and only a very small number of myopic eyes with a high degree of ptosis or severe refractive medium opacity are similar. The pathogenesis of two types of experimental myopia is different. For example, the form deprivation of myopia can still occur after the optic nerve is cut off, but the occurrence of near-myopia is inhibited, and dopamine inhibits the occurrence of form deprivation myopia. However, it is not effective for near-sighted myopia, so the results of form deprivation myopia should be used with caution when applied to human myopia, so as not to be misleading.

In a nutshell, in the individual differences that determine the occurrence of simple myopia, genetics and the environment play about half of each, and the genetic effect is slightly greater than the environment.

(2) Mechanism of occurrence: refers to the biochemical, pathological, optical, cell biology and molecular biological changes that cause myopia, the main factors determining eye refractive power are corneal curvature radius, lens power and axial length, Sorsby believes that If there is an abnormality, it can cause myopia. All three are within the normal range. As long as the combination is improper, it can also cause myopia. In recent years, the measured results show that the main single change of simple myopia is the axial length and the radius of curvature of the cornea. The relationship is small.

When human myopia occurs, the mechanism of axial elongation is related to the weakness of the sclera, especially the posterior sclera. The scleral structure mainly includes cells (fibroblasts) and extracellular matrix (collagen fibers, elastic fibers, aminodextran). And proteoglycans, etc., the weakening of both forces can cause the axial length to prolong, mammalian experiments have also confirmed that there are weak sclera in myopia, collagen fiber, proteoglycan and aminoglucan reduction and matrix metalloproteinase increase The scleral structure of the chicken is different. In addition to the fibrous layer, there is a cartilage layer. When the myopic eye is thickened due to the thickening of the cartilage layer, the thickening of the sclera is strengthened. Therefore, the axial length is the result of increased scleral tissue, active elongation, and breastfeeding. Animals are the opposite, so the results of chicken studies cannot be arbitrarily applied to humans. The results of mammals, especially primates, may be closer to humans when doing myopia experiments.

Experimental myopia studies have found that there are some biochemical substances in the retina that increase or decrease during the formation of myopia. For example, vasoactive intestinal peptide may promote myopia; dopamine may inhibit myopia, which is related to myopia. The substance acts on the retinal pigment epithelial cells and choroidal cells (mainly melanocytes) to produce the next level of biochemical substances, which act on the sclera, and the biochemical substances that promote myopia can inhibit the growth of scleral fibroblasts and extracellular matrix. The synthesis, or degradation, destroys the extracellular matrix, causing the sclera to weaken and myopia, and the final level of the myopia-related substances in the sclera is not fully understood. It has been found that there may be various growth factors, retinoic acid and metalloproteinases. At present, most studies on myopia are still at the level of organs and tissues. In recent years, many human eye cells have been cultured in vitro and applied to myopia research, which can help to clarify the incidence of myopia at the cellular and molecular levels. mechanism.

In addition to the extension of the axial length, the regulation also plays a certain role in the occurrence of human simple myopia. The adolescent simple myopia can reduce or disappear after the ciliary muscle paralysis, which is called pseudomyopia. There are two different views. One is that the near vision can cause the adjustment of the sputum. Anyone who has the sputum adjustment is a pseudo-myopia. At this time, if the measures are relaxed, the vision can be restored. If the eye is continued, excessive use can cause The axial length is extended and converted into true myopia. The other is that pseudo-myopia refers to the disappearance of myopia after ciliary muscle paralysis. Such myopia is very rare. During myopia, myopia is regulated. Important, but not the only factor.

According to a large-scale domestic survey, the myopia of 5% to 8% of patients with ciliary muscle paralysis after adolescent myopia disappeared completely, that is, pseudo myopia, which is completely caused by regulatory factors, and about 50% of myopia is basically unchanged. For true myopia, it is caused by organic changes (mainly axial lengthening). The other 42% to 45% of myopia, the degree is reduced but not completely disappeared. This is semi-authentic myopia, which is caused by adjustment and eye axis changes. In common, in addition to regulation, the ratio of regulatory set and regulation (AC/A) plays a role in the pathogenesis.

2, pathological myopia

The pathogenesis of myopia occurs more closely with heredity. The hereditary mode of pathological myopia is mainly single-gene inheritance, genetic heterogeneity, autosomal recessive inheritance, autosomal dominant inheritance, sexually linked recessive inheritance, etc. Various genetic methods.

(1) Autosomal recessive inheritance: According to the large-scale family survey and epidemiological research in China, the most common genetic pattern of pathological myopia is autosomal recessive inheritance.

Analysis of 1 family: According to the investigation and analysis of a total of 507 families in 7 groups of pathological myopia in China, both parents were pathological myopia, the offspring were close to all cases (93%); the pathological myopia patients did not have both parents (that is, all heterozygous), the correct incidence rate of the same generation is 22.3% (Lentz correction method); such as one of the parents (the other side should be heterozygous), the same generation incidence rate of 45.6%, basically in line with autosomal recession Sexual inheritance.

2 Epidemiological investigation: Some people have made epidemiological investigations on pathological myopia in a certain area of Shandong, and found that the incidence of offspring in various phenotypes is in full agreement with the expected value of autosomal recessive hypothesis.

3 Aggregate analysis study: Aggregation analysis of 6 pathological myopia families, the conclusion is that pathological myopia belongs to single gene inheritance, consistent with autosomal recessive inheritance, gene frequency is 14.7%, a few sporadic Cases cannot exclude the existence of autosomal dominant inheritance.

(2) Autosomal dominant inheritance: Some families in pathological myopia have multiple generations of consecutive vertical passages, and the incidence of offspring of multiple individuals in each generation is close to half, which is more likely to be autosomal dominant, due to autosomal recessive inheritance. The pathological myopia has a higher gene frequency (10% to 15%), and the heterozygous frequency in the population is about 18% to 24%. Therefore, patients with autosomal recessive pathological myopia have a marriage with a normal phenotype. One out of every 4 to 5 marriages, one encounters a heterozygote, which causes the offspring (false dominant phenomenon), so it cannot be seen that the vertical passage is considered to be autosomal dominant inheritance.

(3) Sexually linked recessive inheritance: There are a few cases of pathological myopia, only males, and female carriers pass the phenomenon, which is more likely to be sexually linked recessive.

(4) Gene mapping: The gene mapping of pathological myopia has been found to have MYP1, located on X chromosome q28; MYP2, located at 18p11.31; MYP3, located at 12q21-q23; 7q36 and 17q21-22, but this The subjects were all autosomal dominant families, and most of the results could not be repeated in later studies. It can be seen that autosomal dominant pathological myopia has genetic heterogeneity. The locus may only represent a very small number of individual cases, and the mutation genes of most pathological myopia patients are still to be explored. The genes that are actively being explored include genes related to various growth factors and extracellular matrices. Myopia may be related to HLA-DQB1 and is also worth noting.

Myopia prevention

There are many ways to prevent myopia. Any kind of measures that can help reduce visual fatigue and relax eye adjustment can be tried. Of course, other ways can be explored, but they should be scientific and reasonable, and beneficial.

1, prevention of myopia

There is a certain regularity in the occurrence of myopia. It should pay attention to eyesight health care during the pre-existing period, usually including preschool age, growth and development, pregnancy, perinatal period and certain systemic diseases. Simple myopia has a clear external cause. Long-term use of eyes at close distances, so reducing visual load is the key to preventive work. Through regular monitoring of visual changes and qualitative examination of visual acuity, early detection and identification of preventive subjects can be made. According to epidemiological investigation, the following subjects are more likely to occur. Myopia can be used as a key prevention target:

(1) Have poor eye hygiene habits and excessive close workers.

(2) Parents are nearsighted.

(3) The visual instability has decreased from 1.5 to 1.2 or 1.0 (actually there may be myopia), preventive measures include continuous short-term use of eye time should not be too long; active participation in outdoor activities; , or a variety of vision and adjustment - collective training method, in order to increase the line of sight frequently, broaden the horizon, relax the regulation, maintain normal visual function, usually ensure adequate sleep, work and rest, balanced diet, reasonable nutrition, life to Regular, maintain physical and mental health, pay attention to prevent all kinds of abnormal stimuli and risk factors, such as organic phosphorus chronic poisoning, etc., try to avoid the formation of shadows on the retina, such as early correction of corneal astigmatism, not under shock or shaking conditions or Reading at dusk, lighting requirements are full and standard, the light should not be too dark or too strong, the TV screen brightness and color tone should be moderately normal, the image should be adjusted in time when the image is unclear, or the line of sight can be shifted, the correct reading position, read and write distance Keep above 1 foot, improve learning conditions (clear print requirements, font standards) and writing conditions (clear handwriting, white paper), active treatment Physical illness and other eye diseases, especially during adolescents with systemic fever, should protect eyesight, pay attention to eye hygiene, prevent pathological myopia through genetic counseling, both parents are pathological myopia, children are nearly 100 % Onset, prevent infection during pregnancy, avoid poisoning, allergies and other abnormal stimuli. Premature babies should pay attention to care and reduce oxygen intake as much as possible.

2, prevent the increase of myopia degree

For all myopia, especially those with pathological myopia, we should try to prevent the myopic diopter from deepening and maintain or strive to improve the visual function. In addition to the above methods for preventing myopia, we should pay special attention to the rational use of the eye and choose appropriate work. Avoid excessive use of eyes and bad visual stimuli, correct correcting ametropia, wear appropriate glasses, pathological myopia requires frequent wearing glasses, close to use, or wear contact glasses, may reduce or stop the development of myopia Measures include glasses (dual-focus lenses, oxygen-permeable rigid contact lenses), drugs and surgery.

3, prevention of complications of myopia

The main cause of blindness in myopia is its complications, such as amblyopia, retinopathy and glaucoma. It should be actively and carefully taken to prevent the deepening of myopia. In addition to requiring patients to pay attention to changes in vision, they should also Pay attention to any other abnormal phenomena that occur early in the eye, such as flashing, fly (mosquito), visual field defects, progressive or sudden decline in vision (especially near vision), and soreness, pain and night blindness in the eyes. Phenomenon, if you have a complication at one glance, you should observe the other eye condition at any time, check it at any time, and find it early, including changes in intraocular pressure, visual field, and axial axis. If necessary, perform other special eye examinations. Pathological myopia occurs. The incidence of angina glaucoma is high, and the changes in the fundus and visual field can mask the glaucoma lesions. Because the eye wall hardness is low, the measured intraocular pressure is low, which can delay the diagnosis of glaucoma. Therefore, it should be vigilant against pathological myopia. When measuring eye pressure in the eye, a flattening tonometer should be used to eliminate the influence of the hardness of the eye wall. In addition, various predisposing factors should be avoided to reduce the bad stimulation to the eye. Minimize intense physical activity.

4, promote eye exercises

(1) Eye exercises: The Ministry of Education and the Ministry of Health have designated the students' eye exercises. Although some scholars have different opinions on their effects, as long as they can do it according to the regulations, it is beneficial to the health of the eyes.

(2) Far-reaching method and crystal gymnastics: These two kinds of eye-operating exercises are based on the "long-term view of the main cause of myopia", and it is designed to prevent the occurrence of myopia. The class method is described in detail in all popular science books for prevention and treatment of myopia, and will not be described.

(3) Finger exercises: There are two ways to do this, which are described as follows:

1 target finger operation: straighten the index finger of the right hand and place it vertically 15 to 25 cm in front of the eyes. When the eyes are looking at objects other than 10 m away from the distance, the eyes are in a far-sighted state. At this time, the eyes of the two eyes are scattered. Open can make the eyes of both eyes parallel, the two eyes adjust to zero and the pupils enlarge. When the two eyes look at the front finger, the two eyes are in a near-reflex state. According to the distance between the index finger and the eye, if placed at 15cm, it can produce 6.6. The adjustment of D and the collection of 6.6 m angle (ma), such as the two eyes alternately looking at the distant object and the near finger, will inevitably make the joint movement of the intraocular and extraocular muscles of both eyes (Fig. 5), which is a very reasonable prevention and treatment of myopia. Eye exercises.

2 finger operation without far target: put one finger vertically in front of the two eyes, when the two eyes look at the near finger, form a double eye single vision so that the two eyes are in a close state, according to the distance between the finger and the eye can be different degrees Synergistic exercise of close-up of the inner and outer muscles of the eyes, but when the subject goes to see the distant target in the imagination, and consciously does not look at the near finger (shown by the dotted line in the figure), the eye axis of both eyes rotates outward. Since there is no gaze target in the distance, the near fingers are seen as two blurred fingers pointing left and right, and then the eyes are gazing at the front finger, and suddenly the imaginary distant target is seen, and the finger operation without the far target can be performed (Fig. 6 ), if you move your finger up and down at the same time, you can exercise the ocular and external muscles of both eyes. This method is simple and convenient to do at any time and any place. If you can persist, it is indeed economical and effective in preventing and treating myopia. A good way.

Myopia complications Complications retinal detachment malnutrition anisometropia amblyopia strabismus open angle glaucoma

The harmfulness of myopia is mainly due to complications. In addition to the general low visual function such as distance vision and the unique signs (leopard-like fundus and arc-shaped plaques), the complications of myopia are various, usually with the deepening of diopter. And gradually increase and aggravate with age, resulting in more damage to visual function, and due to damage of choroidal retinal degeneration, macular degeneration and retinal detachment, it can cause blindness, and the pathological basis of complications is mainly eye Axial elongation, blood circulation disorders, malnutrition and specific tissue degeneration, common complications include:

1. Vitreous, choroidal and retinal degeneration caused by dystrophic dysfunction due to abnormal eye structure;

2, due to the extension of the axial length, scleral elongation, macular degeneration caused by biomechanical abnormalities and posterior pole petroma;

3, due to low vision, anisometropia and adjustment of congenital dysfunction caused by amblyopia and strabismus, a variety of pathological manifestations can be seen as a complication of myopia, can also be attributed to the signs of degenerative myopia, There are complex causal relationships.

details as follows:

1, vitreous lesions

Myopia has a characteristic vitreous change. Due to the extension of the axial length, the vitreous cavity is enlarged, which promotes the progressive degeneration of the vitreous, resulting in liquefaction, turbidity and detachment. The colloidal vitreous liquefies and the normal truss structure is destroyed. The emptiness of the optical gap, the original tissue-like fiber scaffold tissue is incomplete, when it is a bit, strip, block or membranous turbid floating object, these free objects flutter more clearly during eye movement, so there seems to be The phenomenon of flying flies and flies, as the axis of the eye continues to stretch, there may be some gaps between the vitreous and the retina, the gap is filled with lymph, which forms the vitreous and then detaches, and then detaches under the ophthalmoscope into a fish mouth, round Or elliptical, the slit surface under the slit lamp is strip-shaped, followed by a transparent liquid, the vitreous detachment plus the degeneration and contraction of the vitreous to the retina, and easy to cause retinal detachment.

2, cataract

Due to abnormalities such as intraocular blood circulation disorder and tissue degeneration in myopia, the lens can also be affected, mainly characterized by opacity of the lens, turbidity can be posterior pole type, nuclear, brown-yellow, slow progress, nuclear In turbidity, due to the increased refractive power of the lens, the degree of myopia can be deepened temporarily. In the complication of lens operation and postoperative surgery, there are more myopia than those without myopia. In addition to cataract, myopia may also cause lens dislocation.

3, glaucoma

In myopic patients, the prevalence of open-angle glaucoma is 6-8 times that of normal people, and the proportion of normal tension glaucoma and suspected glaucoma is also significantly higher than that of other people. In open-angle glaucoma patients, myopia accounts for 46.9%, usually more common in children under 40 years old and more than 26.5mm in the axial axis, patients may have blind spots earlier, the physiological blind spot is larger than normal eyes, and the intraocular pressure is mostly mild, with an average of 5.02kPa (37.74mmHg). The aqueous flow fluency coefficient (C value) is lower, the patency ratio (Po/C) is higher, the aqueous humor flow is lower, the corneal curvature is larger, the scleral hardness coefficient (E value) is lower, the anterior chamber is deeper, and the optic disc border is Fuzzy, color contrast is not obvious, the depression is more atypical, but the ratio of cup to plate is higher than normal, the phenomenon of blood vessel bending and displacement is not obvious, the positive rate of corticosteroid induction test is higher, and some degenerative myopia is accompanied by high intraocular pressure. At the same time, the edge of the optic disc becomes steeper and more frequent before the visual field changes and the optic disc sag enlarges. Due to the slow course of the disease, the signs of glaucoma are not obvious. The early abnormalities are mostly confused or concealed by the performance of myopia (as usual glaucoma) Visual disc depression For the possible manifestation of myopia, etc., glaucoma associated with degenerative myopia is often missed, especially when the intraocular pressure is measured by the Schiötz tonometer, and the eye wall of the myopic eye is thinner. It is low, so the myopic pressure can be measured by myopia. If using Schiötz tonometer, scleral hardness (E value) and corrected intraocular pressure (P0) should be recorded. For myopia with higher degree, If there is an unexplained decrease in vision and a rapid increase in diopter in the short term, attention should be paid to the possibility of glaucoma. The presence of glaucoma can accelerate the pathological process of myopia, causing more organic and functional damage. The degenerative myopia and glaucoma interact with each other, which can eventually lead to a vicious circle: elevated intraocular pressure, which promotes the extension of the axial length; and due to the extension of the axial length, the choroidal retina becomes thinner, and the microcirculation and blood supply are further affected. The function is more susceptible to damage from high intraocular pressure. Intraocular pressure should be understood to include both elevated intraocular pressure and intraocular pressure, although the intraocular pressure is normal, but the tissue that withstands the intraocular pressure is weak and the resistance is low. Pathology, recently decided to study the influence of genes between glaucoma and myopia mutual decision indicates that there may be more on the link between the two has genetics.

4, macular degeneration

(1) Macular hemorrhage: common macular hemorrhage in myopia, the incidence rate can reach 4.5%, the age of good hair is: 20 to 30 years old and >60 years old, diopter more> -8D, bleeding or repeated bleeding, can cause Proliferative changes and pigmented lesions, poor prognosis, severely affect visual function, more manifestations of visual loss, central dark spots and allergies, etc., when bleeding is not in the fovea, although the visual acuity can be slightly reduced, but there are relatively dark spots The visual acuity of the foveal hemorrhage is obviously decreased. The visual acuity can be slowly recovered after hemorrhage, but it is difficult to restore the original state, leaving more abnormalities such as deformed vision and darker spots. Macular hemorrhage can usually be divided into two types:

1 simple macular hemorrhage, more common, accounting for 62% of patients, the age of onset is light, the bleeding range can reach 0.25 ~ 1PD size, there can be one or several bleeding spots in the fovea, multi-dose pigment epithelial layer The bleeding can reach the deep layer of the retina in a long time. The blood comes from the choroidal capillaries, which is caused by the excessive extension of the ocular endothelium to the choroidal capillaries. It usually takes 2 to 3 months to absorb, leaving no traces, and a few can be atrophied by pigment epithelium. Leave a point or line defect, repeated bleeding can cause paint crack-like lesions, bleeding also suggests that myopia may be developing.

2 angiogenesis type macular hemorrhage, accounting for about 32% of patients, bleeding range is about 1/2 ~ 2 / 3 optic disc size, accompanied by yellow-white exudation plaque and gray-white structure, fluorescent angiography can be spotted and reticulated at the beginning In the late stage, the neovascularization from the choroid invades the Bruch membrane, and a new vascular network can be formed in the deep layer of the retina. Plasma leakage can cause a proliferative response, and scarring occurs after 3 to 6 months. Scarring), this process may be the same as the mechanism of age-related macular degeneration, but myopia is also accompanied by axial lengthening, Bruch membrane and pigment epithelial damage.

Macular hemorrhage can be regarded as one of the lesions of Fuchs plaque, that is, Fuchs plaque is caused by bleeding, there may be a causal relationship with lacquer crack-like lesions, lacquer crack-like lesions can cause macular hemorrhage, and paint cracks after hemorrhage absorption Widening, and the number increased, 97% of those with macular hemorrhage may have paint crack lesions (some are found after bleeding absorption), and may have bleeding in the early stage of macular pigment abnormalities.

(2) macular degeneration: myopia with macular degeneration is more common after 60 years of age, due to the disappearance of the choroidal capillary layer of the nutrient macula, or choroidal occlusion due to macular area, causing atrophy of the neuroepithelial cells in the macular area and eventually degeneration (including Cystic degeneration and discoid degeneration, etc., can occur alone or as part of the entire myopic choroid-retinopathy.

(3) macular hole: the macular area due to long-term dystrophic pathological changes, plus retinal anterior membrane traction, based on the original degeneration or scar and retinal-vitretic adhesion, the occurrence of holes, and thus caused retinal detachment, women and old age More people, general myopia are > -8D, especially in the existing grape swollen.

5, retinal detachment

Retinal detachment is a common complication of myopia, the incidence rate is 8 to 10 times that of other people. In primary or rhegmatogenous retinal detachment, the proportion of myopia can be as high as 70% or more. , high myopia (-5D ~ -8D), multiple ages 21 to 30 years old and 51 to 60 years old, the pathological basis of retinal detachment is the formation of retinal tears, due to degeneration of vitreous and degenerative or cystic degeneration Retinal adhesion, under the long-term continuous traction of the vitreous body, including external force, some parts of the degenerated retina are pulled out of the hole or tear, the liquefied vitreous can flow from the rupture into the subretinal, so that the retina is bulged and detached, and the retinal degeneration is more Occurred in the equatorial and peripheral parts, so the holes are more common in the corresponding parts, especially in the upper quadrant (the cystic degeneration is more common here), the hole is mainly horseshoe-shaped (there can be a vitreous cover), but also has a round shape Or elliptical, early due to degeneration of the vitreous to the retina, can cause some signs of stimuli, such as flashing, etc., followed by visual field defects and decreased central vision.

6, posterior scleral staphyloma

In the degenerative myopia, the eyeball is extended from the equator to the back, the posterior sclera is obviously thinner, and localized expansion occurs. Under the action of intraocular pressure, the sclera bulges to form posterior scleral staphyloma of different sizes (posterior scleral) Staphyloma), its occurrence is closely related to the degree of diopter and the length of the eye axis. Curtin reported that in the axial length of 26.5 ~ 27.4mm, the incidence of posterior scleral staphyloma accounted for 4%, while the axial length was 33.5 ~ 36.6mm Among them, it can be as high as 71.4%. According to different forms, grape swollen can be divided into 10 types, including 5 kinds of complex type and 5 kinds of original type, such as posterior type I, macular area type II, optic disc type III, optic disc nose. Lateral type IV and V-shaped under the optic disc, the fundus examination can be seen in the posterior pole of the choroidal retina large-scale thinning, atrophy, irregular borders, between the optic disc and the macula, or limited to the macular area, strong light transmission, clear blood vessels The pigment is free, and some may be accompanied by bleeding, or macular hole, and the position of the optic disc is also significantly changed. The posterior swell is equal to the extension of the axial axis, and the bottom of the retina is larger than the refractive power of the retina at the edge, that is, myopia deep, Therefore, it can also be based on the diagnosis of grape swollen, and some grape swollen around the optic disc, grape swollen can make the visual function more difficult, the prognosis is worse, 1/3 of the patients corrected visual acuity <0.1, blindness rate high.

7, amblyopia

Because the myopia of myopia is generally normal, there are fewer amblyopia, but the myopia of >6D has the same chance of occurrence as hyperopia. The possible conditions of amblyopia are monocular myopia, myopic anisometropia, and obvious strabismus. High myopia starting in early years.

8, strabismus

Myopia is often accompanied by a recessive exotropia or a dominant exotropia due to abnormalities in the regulation and aggregation function. It can be seen in various degrees of myopia, progressive development, and gradually changed from recessive external oblique to obvious Sexual exotropia, which is usually caused by wide facial shape, large interpupillary distance and refractive error of both eyes. A variety of visual functions, including near vision, correcting far vision, collection and binocular vision can be normal in the early stage, but along with The development of oblique, visual function is also gradually obstructed, such as the impact of the collection function, often can cause visual fatigue, especially near-eye workers, and when the angle is too large, can induce disuse of amblyopia and loss of stereoscopic function, some Myopia may also cause esotropia due to dysfunction of eye muscle balance, premature infants with high myopia, and those with esotropia. There are two other special types in myopic esotropia: one is seen in young people, gradually occurs, The performance of esotropia in the near and far vision is different, basically belongs to the commonality, and the other kind of myopia is deeper (-15D ~ -20D), and gradually develops and increases. The passive traction test is seen in all directions. Limit, eventually can appear fixed esotropia.

Myopia symptoms common symptoms pseudo-myopia leopard-like fundus fundus myopia pre-eye shadow fatigue eye dry lens opacity blind spot paving stone degeneration visual distortion

Clinical manifestation

1. The distance vision is reduced and the near vision is normal;

2, visual fatigue;

3, can occur external oblique or co-rotation exotropia, strabismus is mostly a high degree of myopia;

4, high myopia often appear vitreous liquefaction, turbidity, and cataracts and consciously black shadows or vision loss;

5, low, moderate, generally no change in the fundus or leopard-like fundus, myopia, solitary plaque, high myopia, optic nerve nipple or peripheral annular choroidal atrophy, macular degeneration, hemorrhage, Fuchs (Fuchs),;

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Diagnose based on

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Differential diagnosis

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