Why do some people have astigmatism in their eyes?

There are many reasons for it, the most important of which is due to changes in the curvature of the cornea of the eye. The cornea, also called the "black eyeball", is a window in front of the eyeball, which is not only smooth and transparent, but also has a complete hemispherical shape. Its main function is to concentrate the light through light, so that it enters the pupil to reach the retina of the fundus, and then reflects it to the brain, so that people can clearly see the outside world.

Therefore, when the curvature of the hemispherical cornea changes, like an uneven lens, the surface is uneven and irregular, and the external light cannot form a focus on the ancestral omentum. Tian is diffuse in all directions, so that the brain's perception of external objects appears blurred, so that astigmatism is produced. This astigmatism is medically known as irregular astigmatism.

Because the curvature of the cornea changes so much, it is difficult to correct with glasses. There is also a type called regular astigmatism, which is caused by the curvature of the cornea when it is not in a certain direction and its perpendicular direction. There are many types of it, including simple farsighted astigmatism and simple myopic astigmatism; There are repetitive hyperopic astigmatism, recurrent myopic astigmatism and mixed astigmatism, etc., which are mostly caused by the different refractive ability of the cornea, and exist at the same time as myopia or hyperopia, which can be corrected with glasses.

There are two kinds of causes of irregular astigmatism caused by uneven corneal and improper curvature: one is congenital inheritance, and the other is due to acquired corneal disease. As.

If the cornea is ulcerated or traumatized, and scarring occurs after healing, the cornea is uneven and the curvature is not correct. Regular mild astigmatism generally does not affect vision, but there may be uncomfortable phenomena such as eye strain. Many people use their eyes for a long time, which will cause headaches, soreness around the eyes and orbits, and a few people even have symptoms of nausea and vomiting, which have a certain impact on health and work.

As for the astigmatism, when the astigmatism is more severe, the object is blurred, which has more impact on the work. <>

The genetic profile of light varies depending on the cause of the disease. Common causes of astigmatism include congenital and acquired morphological abnormalities of the cornea or lens.

Congenital causes of astigmatism are hereditary, such as astigmatism caused by congenital morphological abnormalities of the cornea. Studies have found that children of parents with astigmatism are twice as likely to develop astigmatism as those of parents without astigmatism. Astigmatism due to various acquired causes is not obviously hereditary.

The acquired causes of astigmatism mainly include: small lumps on the eyelids compressing the cornea, long-term poor eye habits (such as frequent squinting, eye rubbing, lying down and reading, etc.) causing the eyelids to continuously overcompress the cornea, so that the corneal curvature changes and produces astigmatism; In addition, corneal ulcers, corneal scarring, corneal lesions such as keratoconus, or uneven corneal refractive interfaces caused by pterygium can also cause astigmatism; Changes in the lens such as cataracts, lens displacement, etc., can also lead to astigmatism. <>

More than 200 degrees is already a high degree of astigmatism, so generally more than 75 degrees of astigmatism should be paid attention to and corrected in time.

Studies have shown that the most common manifestations of astigmatism in the eye are:

1. The blurred image on the retina needs to be constantly finely adjusted, and the vision is distorted, so astigmatism, especially for farsighted astigmatism, is prone to visual fatigue. Presents with eye pain, tearing, headache, especially in the forehead, double vision, and short-range work that cannot be sustained.

2. Patients with highly asymmetrical astigmatism in both eyes, in order to see more clearly, often adopt a tilted head position to cause strabismus, which can be recovered after astigmatism correction. Patients sometimes move objects closer to the same place as a nearsighted person in order to obtain a larger image of the retina.

3. People with high astigmatism often squint when looking at distant or near targets, so as to achieve pinholes and fissures to improve their vision. Seeing through pinholes or fissures can reduce the impact of astigmatism on vision.

Astigmatism refers to when the eye is adjusted to rest, after the parallel light rays are refracted by the eye, due to the different refractive power of each meridian of the refractive system, causing different degrees of convergence, so it can not be concentrated on the retina, but at different distances to form two intersecting lines, the distance between the two intersecting lines represents the degree of astigmatism, because the retina is only presented as a hazy ring or a line, so the patient feels blurred regardless of farsightedness and near-sightedness.

Astigmatism**:

1 Mild regular astigmatism does not need to be corrected if there is no eye fatigue or blurred vision, but if there is any discomfort above, it should be corrected even if the prescription is not high.

2 High astigmatism should be corrected with cylindrical scope, if not suitable for all correction, can be given a lower degree, the general common method is to take drugs, usually the doctor recommends taking Leyan vision nutrients, warm water, insist on taking for a period of time, astigmatism can be reduced.

3 Irregular astigmatism cannot be corrected with a cylindrical lens, and contact lenses can be tried.

Why do many people with myopia have astigmatism?

There are many causes of astigmatism, the most important being a change in the curvature of the cornea of the eye. The cornea, also called the black eyeball, is a window in front of the eyeball, which is not only smooth and transparent, but also has a complete hemispherical shape. Its main function is to concentrate light through light, so that it enters the pupil and reaches the retina of the fundus, gathers into a focal point, and then reflects it to the brain, so that people can clearly see the outside world.

When the curvature of the hemispherical cornea changes, like an unevenly ground lens, the surface is uneven and irregular, and the outside light cannot form a focus on the retina, which is generally diffuse, so that the brain's understanding of external objects is blurred, so that astigmatism is produced, which is called irregular astigmatism in medicine. Because the curvature of the cornea changes too much, it is difficult to correct with glasses.

Another type of astigmatism, called regularity, is caused by the curvature of the cornea that does not align with its perpendicular direction in one direction. There are many types, including simple farsighted astigmatism, simple myopic astigmatism, recurrent hyperopic astigmatism, recurrent myopic astigmatism and mixed astigmatism, etc., most of which are caused by the different refractive abilities of the cornea, and coexist with myopia or hyperopia, which can be corrected with glasses.

Astigmatism in the eye is due to the inconsistent reflexion of the meridians of the cornea, and the final concentrated image does not form a focal point.

The palpebral fissure of ordinary people is long, and the palpebral fissure has a squeezing effect on the eyeball, so theoretically the eyes should have a little astigmatism, but the degree of astigmatism is different, and the degree of astigmatism is not too large, which can be ignored.

There are also some astigmatism caused by corneal lesions, when the cornea has lesions, the cornea will have scars, or the lens has a hidden disease, which can cause its curvature to be inconsistent in refraction, and the astigmatism formed at this time is irregular astigmatism.

The phenomenon of astigmatism in the eyes is mainly due to the frequent compression of the upper and lower eyelids of the eyes, which forms this phenomenon, and slowly with the increase of age, this physiological defect will have some slight growth, but if it is caused by trauma, then this astigmatism will be very obvious. So you must pay more attention to it.

In addition, in the process of growth and development, abnormal corneal development will also cause the formation of astigmatism, most of the causes of astigmatism in China are related to corneal abnormalities, and a small number of patients may also be caused by abnormal lenses.

It's so professional, and many of them have varying degrees of astigmatism.

Astigmatism is a refractive abnormality of the eye that is related to the curvature of the cornea. When parallel light rays enter the eye, they cannot be concentrated at one point (focal point) because the refractive power of the eyeball is unequal on different meridians, and a clear image cannot be formed, which is called astigmatism. Astigmatism cannot form a clear image by adjusting the effect or moving the distance between the target and the eye, and only with a suitable cylindrical lens can a clear image be formed on the retina.

According to the form of manifestation, astigmatism can be divided into regular astigmatism and irregular astigmatism, the former can be corrected with lenses, and the latter cannot be corrected with lenses.

The causes of astigmatism are:

1.Curvature varies.

That is, the curvature of the refractive surface of the eye is inconsistent, which usually occurs in the cornea but can also occur in the lens. Mild astigmatism, thought to be physiological, is most commonly caused by a greater vertical curvature of the cornea than the horizontal one, usually about the same. It is caused by frequent compression of the upper and lower eyelids, and this physiological defect tends to grow mildly with age.

Those with a large degree of astigmatism are mostly congenital, and acquired ones are often caused by corneal diseases. For example, keratoconus, degenerative lesions around the cornea or scars left after corneal inflammation often cause irregular astigmatism. In addition, irregular astigmatism can also occur when cataract surgery or eyelid masses compress the eyeball.

2.Optical center deviation.

It is mostly caused by astigmatism caused by subluxation or deviation of the lens caused by disease or trauma.

3.The refractive index varies.

It is caused by differences in the refractive rate in different areas of the lens, such as cataract caused by changes in refractive media, which can lead to various astigmatism, distortion of vision and polyopia.

4. Write and read with your head down; reading a book lying down or lying on your stomach; playing handheld game consoles; looking at the flickering light screen for a long time; will cause astigmatism to occur.

Once astigmatism is formed, there will be visual fatigue, vision loss, compensatory cephalic position and squinting vision, and if not corrected, it will affect a lifetime, so it must be paid attention to.

Commonly used methods to improve astigmatism are:

Children with astigmatism first need to supplement vision nutrients in time, it is recommended to take Lejing vision nutrients, twice a day, one pack each time, take it with warm water, insist on taking it for a period of time, and astigmatism will gradually recover.

The other is to develop good eye habits.

1. Regular eye examination 1 2 times a year. Instruct young children to practice good hygiene and not to contact their eyes with their hands or chemicals. When reading, there should be plenty of light, preferably from the left rear; Correct posture and a distance between 30 cm and 40 cm.

2. When choosing reading materials, the font should be clear and not too small.

3. Watching TV must be 5 7 times the diagonal of the TV picture. Read a book for no more than one hour in a row. If you need glasses, you should be examined by a doctor and then dispensed with glasses.

Astigmatism refers to the disorderly vision, which is caused by the improper curvature of the cornea, and the problem of astigmatism often appears in children and adolescents, and the factors that cause astigmatism are as follows:

1. The change of astigmatism during myopia, the eyes look inward and downward, and the eyeball rotates at the same time, which is the change of the astigmatism axis of the eye, so the appropriate lenses can be selected according to the different ages, focus depth and relative adjustment force of the patient.

2. The symptoms of visual fatigue are usually related to age and the nature of the work, the older the person, the person who writes at the desk, will cause mild to moderate astigmatism, if it is lower than the normal value, it needs to be corrected.

3. The impact of spectacle lenses is due to the uneven size effect of the glasses around the moving lens surface, and sometimes the size of the frame may also affect the peripheral optics and cause astigmatism.

What should I do if my eyes are myopic for more than 700 degrees, and parents still can't solve it.

Pay attention to these problems, and our eyes will not appear astigmatism!

Myopia does not necessarily have astigmatism, and in some cases, myopia and astigmatism coexist, but this is not a certainty. Astigmatism is a refractive abnormality of the eye that is related to the curvature of the cornea. Some people have a curved cornea in one angle and flatter in others.

The cause of astigmatism is that the refraction rate of each meridian of the cornea is inconsistent due to the uneven thickness of the cornea or the uneven curvature of the cornea, so that the light rays passing through these meridians cannot be concentrated at the same focal point, and the light rays cannot be accurately focused on the retina to form a clear image, which is called astigmatism. Clinical manifestations: patients with low refractive power can be asymptomatic, slightly higher astigmatism may have vision loss, vision is not clear at far or near, there seems to be double vision, and there are often symptoms of visual fatigue.

Ophthalmologist Shi Yongli Profile: Director of the Department of Ophthalmology, working in a tertiary hospital for more than 10 years, good at cataract, glaucoma, pterygium surgery and various ocular surface diseases, dry eye syndrome, keratitis and pigmentitis, fundus disease, various complex eye diseases, systemic diseases, ocular complications and difficult diseases.

Including optical correction** and surgery**. Wearing a cylindrical lens for optical correction is the main method of astigmatism.

1.Regular astigmatism.

It can be corrected with different cylindrical lenses according to the type of astigmatism and the degree of astigmatism. Convex column lens for farsighted astigmatism, concave column lens for myopic astigmatism.

Mild astigmatism does not need to be corrected if there are no clinical symptoms, and corrective glasses should also be worn if there is vision loss or symptoms of visual fatigue and visual interference.

Children, especially preschoolers, must adequately correct astigmatism to prevent the formation of amblyopia.

Before wearing, it should be refractioned, adolescents and children should be dilated refraction, and it can also be combined with the measurement of keratometer to understand the nature and degree of real astigmatism, and then combined with subjective audition, the prescription of glasses can be determined.

Patients with high astigmatism who cannot adapt to spectacles can be corrected with contact lenses.

2.Irregular astigmatism.

It is not easy to correct with lenses, and can be corrected with contact lenses.

3.Surgery. It is suitable for high astigmatism caused by congenital or acquired eye surgery such as cataract or corneal transplantation, such as excimer laser refractive corneal surgery, laser corneal thermoplasty, cornatotomy, etc.