Myopia (Myopia) is the eyes can not see Qingyuan objects, but to see the symptoms of near objects. Under the premise of static refraction, d
Myopia (Myopia) is the eyes can not see Qingyuan objects, but to see the symptoms of near objects. Under the premise of static refraction, distant objects can not converge in the retina, and in the retina before the formation of the focus, resulting in visual distortion, resulting in blurred objects far away. Two types of myopia. Refractive myopia is the most serious. Refractive myopia can reach more than 600 degrees, that is, high myopia.
Classification of myopia
1 according to the degree of myopia
The 3.00D (300 degrees) or less, known as mild myopia.
The 3.00D ~ 6.00D (300 degrees ~600) for moderate myopia.
The 6.00D (600 degrees) above for high myopia, also known as pathological myopia.
2 according to the refractive components
The axial myopia eyeball, is due to the excessive development.
The bending degree of myopia, is due to the cornea or lens surface caused by bending through strong.
Quguang rate of myopia, refractive diopter is caused by excessive.
Accommodative myopia. It is caused by the relaxation of the remote regulation. It is with the refractive components change true sex myopia is different in nature.
4 mixed myopia
Often a person is due to fatigue caused by eye myopia pseudomyopia, cause slowly true myopia and pseudomyopia part synchronization, can be said that in myopia deepened the people inside, are mixed in the treatment of myopia, myopia is the most effective physical means nothing more than two kinds, one is due to surgery. The current operation situation is not so clear sequelae, there is no way to explain the shortcomings, has the advantages of quick.
Myopia is caused by a variety of factors. In recent years, many evidences indicate that environmental and genetic factors in the occurrence of myopia: external - long time to see things close to the eye lens and the ciliary muscle loss of elasticity causes the lens can not be restored (born than thick), so the occurrence of myopia.
Genetic factors: the study found that parents with high myopia, the incidence of the next generation of myopia, myopia has a certain genetic predisposition has been recognized, especially for high myopia. However, it is not obvious to the general myopia.
Environmental factors: the occurrence and development of myopia and close relationship with the eye is very close. Young people's eye is in the growth stage, adjustment ability is very strong, stretching the eyeball is relatively large, reading and writing near work, play a role not only need to adjust the eye, double eye and extraocular muscle cohesion, so put some pressure on the eye, in the course of time, before and after the axis of eyeball may be long. Each increase of 1 mm of -3.00 diopter (i.e. ordinary said 300 degrees), of course, the vast majority of myopia myopia, general degrees are relatively low, in 6 diopter following onset in adolescence, before and after, the development is very slow, they have this kind of myopia is called true myopia to distinguish pseudomyopia.
(1) close to the eye. According to the relevant information, young people with myopia eye to eye with a long distance is too close to see. Young eye diaojieli is very strong, when the book and eye distance of 7-10 cm can still see the object, but if this distance is often read, write tension will make the abnormal regulation of the eye, thus inflectional (regulatory) myopia, the so-called pseudomyopia. If the long-term excessive regulation, not flexible because of ciliary muscle, caused by excessive regulation to strengthen the convergence effect, make the extraocular muscle to exert pressure on the eyeball, increased intraocular pressure, intraocular tissue hyperemia, and teenagers eyeball tissue delicate, eyeball compression gradually extended, eyeball becomes longer, than the normal value on the formation of the shaft myopia, the so-called true myopia. Normal reading distance should be 30-35 cm.
(2) the eye time is too long. Some young people to read and write and do homework, watch TV and other continuous 3-4 hours without rest, even the night before sleep and rest, which not only affect the body health, but also make the eyes burden, intraocular muscles long time in a state of tension and not rest, in the course of time, when looking at the distance, the eye muscles can relax a spasm so far, feel vague and myopia. Some students have a significant decline in summer vision is the reason. It is generally believed that a continuous reading or writing or watching TV for 40-50 minutes should rest for a while or look at a distance.
(3) illumination light is too strong or too weak. If the light is too strong, such as sunlight written, will cause a strong reflection, irritation of the eyes, make eye discomfort, it is difficult to see the font, on the contrary, the light is too weak, writing poor lighting, eyes can not clearly see the font, the head will move, close to the book, the above two kinds of circumstances can eye fatigue, eye regulation of excessive or spasm of myopia.
(4) reading while driving or walking. Some young people make full use of time, while walking or reading a book in the car in the car, which is bad for the eyes. Because the car is shaking, the body is shaking, eyes and books can not be fixed, coupled with poor lighting conditions, increasing the burden on the eyes, often so it may cause myopia.
(5) lying reading. Many teenagers like to read in bed. It's a bad habit. Because people's eyes to maintain the level of the state of reading, so that adjustment and collection (influx) agreed to reduce eye fatigue. If you read on the bed, eyes in the state level, distance between eyes and a book is not consistent with the view about the books are inconsistent, uneven illumination, will make the eyes and easy to adjust tension in the book closer to the eyes, it can aggravate the burden on the eyes of 2-3 times, day long form myopia.
(6) lack of sleep. When the lack of sleep, the second day tired, dizzy, the brain is not fully rest, failed to eliminate fatigue, heavier burden on the eyes, the occurrence of myopia. Lack of sleep is one of the most important reasons for the formation of myopia.
(7) the desk does not meet the requirements, writing posture is not correct. If the chair is too low, the head forward, spinal curvature, chest compression, relatively tight regulation of eyes. Or the table and chair is too high, both feet dangling, the lower limb is easy to swing, can not maintain the correct posture, can make the eye fatigue, as time passes, prone to myopia.
(8) the impact of the current space rays. Often watch TV, especially the lack of signal, the receiving rate is not high in rural areas, no common antenna, the screen is not clear, the snow is much, it is easy to make eye fatigue, the students often play computer games more easy to damage eyesight, shopping malls selling bully machine learning, can directly cause myopia, today computer is a necessary course, long operation caused by dryness and fatigue caused by eye myopia, are required to properly control the use of time.
(9) the degree of curvature of the cornea or the curvature of the anterior and posterior part of the lens becomes larger, which is mostly congenital, and is rarely seen clinically.
What is false myopia
Pseudomyopia is relatively true myopia. True myopia is the refractive system of the eye that is in a static state, that is, in addition to the regulation of the role of the eye is located in the far distance. In other words, myopia is due to congenital or acquired factors caused by the anterior and posterior diameter of the eye becomes longer, parallel rays into the eye before the formation of the focus in the retina, causing blurred vision. The pseudo myopia, is to see distant objects when there are some regulatory role to participate.
Common in young students looking at near objects, due to the use of the level of regulation is too strong and too long duration, sustained contraction caused by the ciliary muscle, adjust tension or spasm caused by trned, so in the long time to read and write to see far, cannot quickly relax regulation, resulting in dizziness, eye swelling decreased visual acuity, visual fatigue symptoms. This is due to the increase in the refractive power of the eye, so that the eye in myopia, known as pseudo myopia. Pseudomyopia and true myopia from symptoms are visual fatigue, visual acuity is not good and good eyesight characteristics. But pseudomyopia is a functional change, no longer the eyeball, just a spasm of accommodation, were cycloplegics, most can be converted to hyperopia or emmetropia. If the true myopia treatment with myopia lens, the eye will feel very uncomfortable, because it did not relieve the spasm of accommodation, and even lead to dangerous development of myopia.
What is the true myopia
True myopia: also known as axial myopia, refractive interstitial refractive power is normal, before and after the axial diameter increased, the distant light eyes after the image on the retina before.
The main clinical features are as follows: the true myopia degree of myopia for moderate and high myopia, occurrence and development for a long time, and different degrees of eyes with convex appearance. The true myopia is difficult to self adjustment and recovery.
We believe that the biggest difference between true myopia and pseudomyopia is refractive interstitial (cornea, lens, vitreous body, waterproof) refractive normal, and long axis. The main reason for this is that the long distance.
Symptoms of myopia
1 dysopia myopia mainly decreased visual acuity, visual is blurred, near normal vision, but often because of high myopia refractive media opacity, retinal and choroidal degeneration, the vision is not good, sometimes accompanied by a shadow floating eyes.
2 of the patients with moderate or high myopia in the near field, the use of little or no adjustment in the near field, the corresponding reduction of the role of radiation, can cause eye position outward deflection, the formation of exotropia.
3 patients with visual fatigue myopia accommodation is very good, but when in need of excessive use of force of convergence close, thus destroying the balance coordination between regulation and accommodation, resulting in muscular asthenopia symptoms. The performance of the eye swelling, eye pain, headache, visual objects, such as double shadow virtual edge and other symptoms.
4 highly myopic eyes due to the growth of the service axis, the eye becomes larger, the appearance of the external appearance of the eye protruding.