Why do you need to wear eyes for myopia, what is the effect, and should you use the principle of con

Some principles of prescription glasses for myopia.

1. Before refraction, the interpupillary distance should be measured first, and the corresponding audition frame should be found for refraction.

2. For those who wear low power (no more than the first wearer, the aberration reaction after wearing glasses should be considered, and the diopter should not be exceeded, and the pseudomyopia should be carefully halved or reduced; For moderate and high degree patients, when recovering light, if acceptable, give an appropriate prescription, wait for 2 to 3 weeks, and then strengthen after adaptation, and so on, until the match is in place.

3. For patients who have previously worn glasses, due to the long interval between changing glasses and the increase in power is too large, it should be appropriately reduced, and in the case of acceptability, after adapting to 2 to 3 weeks, the diopter should continue to be increased until it is in place, but it is necessary to master the principle of glasses for myopia: the minimum power of optimal visual acuity.

4. If the patient's original interpupillary distance is too large, such as 70mm, and the actual interpupillary distance is very small, such as 60mm, use the examination frame that is larger than the actual interpupillary distance to try it for more than ten minutes, if there is no discomfort, you can replace the close or consistent with the actual interpupillary distance of the examination frame and repeat the trial for 10 15 minutes, when uncomfortable, choose the best interpupillary distance test frame, wear the glasses equipped according to this interpupillary distance for 1 2 months, and readjust the interpupillary distance until it meets the actual interpupillary distance of the person.

5. For patients with astigmatism, reduce some of the astigmatism and still be able to receive, and replace part of the astigmatism with the corresponding spherical lens. For example, astigmatism can be converted into a spherical lens and added to the degree of myopia, which can reduce the discomfort caused by residual astigmatism.

6. For those who wear glasses with refraction, interpupillary distance and other parameters that meet the national standard, but still have discomfort (excluding the above symptoms), heteropia examination should be considered.

7. For patients with high myopia and over 50 years old, due to the decline of regulatory function, they are advised to go to the hospital for examination, and the lesions of cataract or fundus diseases can also be detected early.

8. If you are over 30 years old (about 35 years old), due to the hardening of the lens, the contraction of the ciliary muscle weakens with age, the ability to adjust becomes worse, and the visual axis is also changing, so it is necessary to pay attention to measuring the visual acuity once every six months. When possible, gradually reduce the diopter to maintain the correct eye environment and improve the discomfort of overtone.

9. For refractive patients with myopia, the distance between the near point is exactly 25 30cm, so they can see near without glasses.

10. Prepare reading glasses, the near interpupillary distance should be less than the distal interpupillary distance of about 4 5mm, if you have high blood pressure and heart disease, it is best not to overcorrect.

11. The inclination of the temples and the beads should be kept at 100 150; The alignment error of each position is not greater, especially the positive and negative landing of the legs should be uniform; The hook of the temple should be naturally bent inward, and the bend should not be killed; The leaf should be adjusted according to the height of each person's nose bridge.

Concave lenses diverge light.

Myopia is due to the fact that the retina is too thick and has a strong refractive ability.

The image is presented in front of the retina.

Use a concave lens to present the image on the retina...

The application of convex lenses in life:

Reading glasses, astronomical telescopes, microscopes, magnifying glasses, projectors, cameras, etc.

Application of concave lens in life:

Lenses for glasses for myopia.

The eyepiece of a telescope.

Now the economy is becoming more and more developed, the Internet of Things is getting faster and faster, and the development of the electronic product market is getting better and better. Nowadays, many people are nearsighted everywhere, and I just hope that everyone can protect their eyes, minimize the time they spend using electronic products, and don't let their eyes be too tired. Myopic eyes with glasses use concave lenses, which can be used to correct myopia.

The eyes are short-sighted, although wearing glasses can reduce myopia, but if you wear it often, it will still hurt the eyes, and the eyes will be sunken if you look without a god.

With the development of medical care now, many people will choose to go for surgery**, but surgery** is also risky and not suitable for everyone. Although myopia can affect personal development, it is still possible to reduce it moderately if you pay more attention to prevention in your life.

Don't stay up late in life, rest well, have a regular schedule and rest time, watch less electronic products, if you have eye fatigue, it will hurt your eyes a lot, you can eat a little more in life, and foods that are good for your eyes, such as fish, can be tried anyway how it is good for your eyes.

If you really want to have myopia surgery, you should still ask the doctor in advance if you can do it? If you can do it, then you can do it, that is, you need to do a lot of examinations before myopia surgery, and you must pay attention to eye hygiene to prevent cross-infection.

At the same time, although children should pay attention to the prevention of myopia, adults should also pay attention, otherwise they will wear reading glasses when they are old, and they will look very small, which will be even worse, and it is inconvenient to do anything.

Concave lenses are used in myopic eyes. It is a concave lens, because concave lenses can better correct myopia and allow myopic eyes to see farther things.

They are all concave lenses, because they can magnify smaller objects and play a good role.

The myopic eye should use a concave lens, which is also the principle of optics in physics, and the eyeball of the myopic eye is mutated, so the light is concentrated through the concave lens.

Concave lenses are used in myopic eyes. Myopic eyes must usually look less at electronic products, and then must use their eyes reasonably, and must eat more foods with high nutritional value.

1. Why do myopic eyes wear concave lenses?

Answer: Compared with normal eyes, the lens (equivalent to a convex lens) is more convex and the focal length is shorter, and objects at photopic distances will be imaged in front of the retina, and the image of the object will appear blurry. After wearing a concave lens with a suitable focal length, the divergence of light by the concave lens can be used to shift the image backward on the retina, so that the object can be seen clearly.

2. Why do you need to wear a convex lens for farsighted eyes?

Answer: Compared with normal eyes, the lens of a hyperopic eye is flatter and the focal length is longer, and objects at photopic distances will be imaged behind the retina, and the image of the object will appear blurry. After wearing a convex lens with a suitable focal length, the convex lens can use the convex lens to converge the light to move the image forward and fall on the retina, so that the object can be seen clearly.

Myopia glasses are concave lenses. Myopia is mainly due to the deformation of the lens, which causes the light rays to converge in front of the retina prematurely. The concave lens plays the role of diverging light, and the concave lens becomes an upright, shrinking virtual image, making the image distance longer, which falls exactly on the retina.

Myopia glasses are concave lenses. The image formed by the concave lens is always smaller than the upright virtual image of the object, and the concave lens is mainly used to correct myopia. Myopia is mainly due to the deformation of the lens, which causes the light rays to converge in front of the retina prematurely.

The concave lens plays the role of diverging light, and the concave lens becomes an upright, shrinking virtual image, making the image distance longer, which falls exactly on the retina. Farsightedness (presbyopia) is the use of a convex lens.

Myopia glasses are glasses that need to be worn after myopia in order to see the distance clearly. The purpose of myopia glasses is to correct vision and allow you to see objects at a distance clearly. In order to maintain a certain ability to regulate the ciliary muscles of the eyeball.

Because distant light cannot be focused on the retina, the vision of distant objects is not clear, but after wearing myopia glasses, you can obtain clear images, so that vision can be corrected.

There are three types of concave lenses: double-concave, plano-concave and convex-concave lenses. The line connecting the center of curvature of the two sides is called the main axis, and the point o of its ** is called the optical center. Light passing through the center of light is not refracted, no matter where it comes from.

The beam of light with parallel principal axis is refracted on the concave lens and diverges in all directions, and the extension line against its divergence direction will be at a point f on the same side as the light source, and the refracted light will be emitted from point f, which is called the imaginary focus.

One on each side of the lens. Concave lenses are also known as divergent lenses. The focal length of a concave lens is the distance from the focal point to the center of the lens. The larger the radius of the lens, the longer the focal length, and in the case of a thin lens, the focal lengths on both sides are equal.

The eyes are convex lenses, and there is no such thing as concave lenses.

Concave lenses are characterized by being thinner in the middle than at the edges, which acts as a divergence to light. Convex lenses are characterized by being thicker in the middle than at the edges, which has a converging effect on light.

The lens of a normal eye refracts light from the outside world and is able to converge on the retina, allowing us to see objects from the outside world.

When the anteroposterior diameter of the lens becomes shorter, the ability to refract light becomes weaker, and the light from near can not converge on the retina, so it is necessary to wear reading glasses made of convex lenses for correction, which is commonly known as presbyopia.

When the anteroposterior diameter of the lens becomes longer, the ability to refract incoming light increases, and when light from a distance passes through the lens, it cannot be imaged on the retina, so it is corrected by wearing myopia lenses made of concave lenses. This type of eye is commonly known as myopia.

Myopic eyes wear concave lenses. Because when looking at near objects, the convexity of the lens must be increased through the contraction of the ciliary muscle, so that the image of the near object can fall on the retina in order to see clearly. Long-term close-up work, such as reading, writing, watching TV, playing game consoles, etc., makes the eyes adjust and tension for a long time, tilt the head forward, continuous congestion in the eyeball, increase the intraocular pressure correspondingly, and tension and compression of the extraocular muscles, or due to the traction of the vortex vein during adjustment, which hinders the flow of blood, weakens the resistance of the sclera, and causes the lens to become excessively convex and cannot be restored to its original state; In severe cases, the anteroposterior diameter of the eyeball is too long, and the image of the object formed by the light reflected from distant objects falls in front of the retina, so that distant objects cannot be seen clearly.

Myopia develops, which requires correction with a concave lens. A portion of the light can be diverted.

Concave lenses are also known as negative ball lenses, and the middle of the lens is thin, the edges are thick, and they are concave, so they are also called concave lenses. Concave lenses have a divergent effect on light. Myopia glasses are concave lenses.

The geometric mapping of concave lens imaging is the same as that of convex lenses. From the top of the object, it also acts as two straight lines: one is parallel to the main optical axis, which is deflected into divergent light after passing through a concave lens, and the refracted light is returned to the main focus in the opposite direction; The other is the image of the object through the optical center point of the lens, where the two straight lines intersect at one point.

Myopia eyes wear a concave lens, through which the light diffuses outward and enters the eye, which is equivalent to magnifying the image of the object.

A convex lens is a reading glass, through which the light is focused inward and before entering the eye, which is equivalent to shrinking the image of the object.