Myopia and farsightedness, do you know what causes them?

Myopia is mainly caused by congenital inheritance or acquired poor eye habits, while hyperopia is caused by the development of the eye axis too short or because the eye refractive is too weak。However, whether it is myopia or farsightedness, it is not a normal state that the eyes should have, and it needs to be corrected.

01. Definition of myopia and hyperopia

What is myopia, simply put, is that the eye is imaged in front of the retina without any external interference. It is a typical situation where you can see clearly in the near distance, but you can see the blur in the distance.

The farsighted eye is the opposite of the myopic eye, which cannot see near objects clearly, but can see distant things very clearly.

02. Causes of myopia and hyperopia

There are many causes of myopia, such as genetics, but usually, as long as both parents are not highly myopic (i.e., above 600 degrees), then the chance of inheritance is still relatively small. More often than not, it is due to poor eye habits, such as using the eyes continuously for a long time and not resting enough, resulting in excessive eye fatigue and a situation that cannot see far away.

The formation of hyperopia is due to the shortening of the eye axis, and everyone is born with farsightedness, but if the acquired vision is not developed well, farsightedness will also be formed. There is also a condition in which hyperopia is formed because the refraction of the eye is too weak, resulting in the inability to see near distances.

03. How to correct myopia and farsightedness

Myopia is usually corrected by wearing glasses or laser surgery, but because the cause of myopia is mainly related to our behavior, it is easy to further deepen the prescription once myopia, even after laser surgery, if we do not pay attention to eye habits, myopia will still form again.

The correction of farsightedness is generally through wearing glasses, but the glasses of farsightedness are concave lenses, and because everyone is born farsighted, many farsightedness will slowly become normal with age.

Whether it is a nearsighted eye or a farsighted eye, it actually needs to be corrected, because under normal circumstances, the eye should be able to see the vision on the eye chart, so it is also very important to protect our eyesight.

Myopia is mainly caused by overuse of the eyes and too tight muscles, resulting in imaging before the retina of the eye, and hyperopia is caused by the relaxation of the muscles of the eye after aging.

Myopia and farsightedness are caused by playing with mobile phones, watching TV, or studying too close to textbooks, too close to mobile phones, and too close to TV.

Both of them have a common cause, which is to stare at something for a long time, which causes their eyes to develop a habit.

Categories: Healthcare.

Problem description: Simple. Analysis:

There are many reasons for the formation of myopia.

1. Affected by genetic factors. If a parent or a parent of a previous generation has a history of myopia, there is a high risk of myopia, which is hereditary myopia.

Second, the influence of self and environmental factors. Such as physical weakness, anemia, malnutrition, and eye hygiene, do not pay attention to work and rest and writing distance, long time **TV, game consoles, computers, etc., but mainly due to the influence of lifestyle habits and failure to take preventive measures as soon as possible.

The eye does not need to adjust when looking at a near object. However, when looking at a near object, the convexity of the lens in the eye increases and expands, which increases the refractive ability so that the object falls on the retina and can be seen clearly. In long-term close-up work, the lens is always in a state of over-adjustment, which causes visual fatigue.

When looking at a close object at the same time, the two eyeballs converge towards the base of the nose, so that the extraocular muscles compress the eyeballs, and over time, the eye axis slowly becomes longer, resulting in myopia. The intensity of light has a certain relationship with the occurrence of myopia. If you work in close proximity under poor lighting for a long time, it is also one of the causes of myopia.

There are three main causes of farsightedness:

1) Axial hyperopia: It is the most common in the hyperopic eye, that is, the anterior-posterior axis of the eye is shorter than that of the emmex eye, and it is also one of the more common refractive abnormalities. At birth, the average human eye axis is about +, and it can be said that the baby's hyperopia is physiological.

With the development, the eye axis also slowly grows, but at the age of 5 there are still 90% of children in the state of farsightedness, and at the age of 16 it decreases to 50%, but because the power is low, it is within the adjustment range, and generally does not feel it. In the process of eye development, some people stop developing the eye due to genetics, environment and other factors, and the eye axis cannot reach the length of the normal eye, which forms axial hyperopia. Generally, the hyperopia seen in clinical practice is mostly within +6d, but it can also be seen that there are hyperopia with a high number, and some can even be as high as +24d.

2) Curvature hyperopia: It is formed by the small surface curvature of any refractor in the refractive system of the eyeball, and is mostly congenital factors, such as congenital flat lens, congenital flat cornea, etc.; There are also cases caused by corneal trauma. In recent years, due to the popularization of refractive corneal surgery, the number of farsightedness caused by overcorrection of myopia surgery has gradually increased, which should be paid attention to, but in the early stage of PRK surgery, because the corneal epithelium has not been completely repaired, it often manifests as a staged hyperopia phenomenon, which should be explained to patients in advance to avoid unnecessary misunderstanding.

3) Refractive hyperopia: caused by the decrease of the refractive index of the aqueous humor and the lens, and the increase of the refractive index of the vitreous, which is relatively rare, mainly in the elderly and diabetics, and some lens dislocations can also lead to farsightedness. In addition, tumors of the eye wall and intraocular area, omental edema, inflammatory masses of the orbit, and even omental detachment can cause pathological hyperopia.

The causes of farsightedness are:

Physiological factors: The anteroposterior diameter of the eye is short at birth, so many infants and young children show a physiological farsightedness. The eye axis grows gradually as it develops, and by adulthood it should become emmetropia or close to emmetropia.

Pathological factors: If due to genetic or external environmental influences, children have dysfunction of eye axis development and cannot reach normal length, and farsightedness may occur; or the presence of intraocular tumors, orbital masses, retrobulbar neobulbar organisms, and retinal detachment, etc., can affect the anterior and posterior diameter of the eyeball.

Therefore, farsightedness in the eyes must be paid attention to in a timely manner.

Surgery can be done for farsightedness, but it also depends on the individual's condition, and the doctor will do a detailed examination before the operation. If the degree of farsightedness is not high, it is not recommended, after all, the surgery is ***. It is safer to wear glasses for correction, pay more attention to eye hygiene, and remember to go to the hospital regularly or use a home optometry to check your eyesight, so as not to deepen the prescription unconsciously.

Hyperopia is a kind of refractive error, generally as long as it is in the period of vision development, that is, under the age of 18, timely detection and timely **, farsightedness can be recovered.

One of the commonly used correction methods for farsightedness is to correct it with glasses, and the other is to take drugs together. It is recommended to take two sachets of Leyan Vision Nutrients every day, and insist on taking it for a period of time, the degree of farsightedness will be reduced, and the vision will be improved. The younger you are, the easier it is to recover.

Myopia refers to the image of parallel light rays (looking far away) in front of the retina after entering the eye, causing the retina to be unclear, which is myopia.

Hyperopia refers to the image of parallel light rays (looking at the distance) behind the retina after entering the eye, causing the retina to be unclear, which is hyperopia.

There are two main causes of myopia

1. Ciliary muscle spasm, resulting in excessive refraction of the lens, is pseudomyopia.

2. After a long period of pseudomyopia, the axis of the eye becomes longer (the eye protrudes), forming true myopia.

Pseudomyopia is temporary, and if it is not timely, it will become true myopia, so it is more meaningful to discuss true myopia (in addition, there are a few congenital myopia, the causes are different, the situation is complex, and the number is small, and it can not be discussed).

There are also three causes of farsightedness: one is due to the short anterior diameter of the eyeball, which is the most common cause. Second, the curvature of the cornea and lens becomes smaller.

It is mostly a congenital factor. Third, it is caused by the decrease of the refractive index of the aqueous humor and the lens, and the increase of the refractive index of the vitreous humor, which is relatively rare.

However, the main cause of farsightedness, the short wheelbase of the eye, and the main cause of myopia, do not coexist, so there is no need to discuss them. And because the probability of other situations that cause farsightedness is small, it is estimated that it is not what the poster wants to discuss, and it is not the main contradiction.

So I guess the "farsightedness" referred to by the sticker is probably "presbyopia".

But what needs to be clarified here is that in fact, presbyopia is not farsighted.

Presbyopia is similar to farsightedness in performance, and it is difficult to see near objects, but the causes of the two are different. Presbyopia is mainly due to the decrease in the contractility of the ciliary muscles of the eyeball and the hardening of the lens after aging, resulting in the weakening of the ability to accommolate and the gradual shift of the focus backward.

Therefore, it can be seen that on the basis of myopia, suffering from presbyopia, when looking at near objects, the near point (the point where the eye can see the nearest object) is relatively backward from myopia, so it shows a certain offset.

However, when looking at distant objects, the lens basically has no adjustment effect, and the eye axis is still very long, so the distant objects are still unable to see clearly, and they are still myopia.

The simple conclusion is as follows:

After myopia, presbyopia, in looking at near objects, the two will offset to a certain extent, but looking at distant objects, it is still myopia.

There is myopia and farsightedness, considering that the occurrence and development of myopia is very closely related to the near use of the eye, the adolescent eyeball is in the growth and development stage, the adjustment ability is very strong, the stretch of the eye wall is also relatively large, the general bad eye habits, or long-term use of the eye, may appear myopia or farsightedness.