Abstract: “pseudomyopia” is reversible and can be eliminated. What about “true myopia”? “True myopia” is caused by abnormal eye structure. When the eyes are in close working state, the eyeballs will converge inward under the action of extraocular muscles and become mild “eye to eye”, otherwise there will be ghosting when looking at nearby objects., Rumor: myopia and presbyopia can offset each other. If you have a little myopia when you are young, you won’t get presbyopia when you are old., Truth: got myopia, won’t old flower when you are old? Of course not. To make this clear, we must first explain the working principle of the eye, what is myopia, hyperopia and presbyopia., The eye is a camera. In fact, comparing the eye to the camera is really wronged. The eye is more precise than the camera, but comparing the two can make it easier for us to understand the problems of myopia, hyperopia and aging. Like the camera, the eye can also be divided into two parts according to its function. The front cornea, aqueous humor, lens and vitreous are equivalent to the lens group of the camera and belong to the refractive system; The back retina is equivalent to the film or CCD of the camera and belongs to the photosensitive system. The refractive system is actually like a lens, which focuses the images of the wide world onto the small retina., The important characteristic of refractive system is refractive power. The greater the refractive power, the stronger the ability to focus the line. The cornea has the largest refractive power in the refractive system, about more than 4000 degrees. But the cornea is a “fixed focus lens”, and the refractive power cannot be changed. The refractive power of the lens is slightly inferior to that of the cornea, about less than 2000 degrees. However, by changing the shape of the lens, the refractive power can be adjusted by more than 1000 degrees, just like the optical zoom function of a digital camera. The combination of cornea and lens constitutes almost all the refractive power of the eye. Through them, the eyes can completely shrink a building tens of meters high and project it onto the retina of several square centimeters., The way the lens regulates refractive power is very subtle. There is a circle of ciliary muscle around the lens, which is connected with the lens through small ligaments. The ciliary muscle and lens compete with each other at ordinary times. When the ciliary muscle is relaxed, it will pull around and flatten and thin the lens. In this way, the degree of the lens will be reduced by hundreds of degrees, and you can have a panoramic view of things in the distance; When the ciliary muscle is tense, the lens will return to its natural state, become round, thicker and have greater refractive power. In this way, you can improve the resolution by looking at things near you. In other words, the tighter the ciliary muscle, the looser the lens and the greater the refractive power. The more suitable it is to see small objects and see more clearly; The more relaxed the ciliary muscle is, the more tense the lens is, and the smaller the refractive power is. The more suitable it is to see a large scene and the larger the range it can see. The eyes can zoom and the refractive ability can be adjusted according to the distance of the object they see, which is realized by the competition between the two brothers, ciliary muscle and lens., Why can you get myopia?, If you read books and watch computers for a long time, your ciliary muscles will often be in a state of tension and gradually adapt to this state. If you look at the distance at this time, the ciliary muscles will not relax when they are used to tension, and the lens can’t become flat and tense. The excess positive degree of this part will make normal people feel like wearing a pair of reading glasses and can’t see things far away. You need to look closer. It is equivalent to that the camera is temporarily locked in “close range mode”, and the distant things are blurred. We call it “myopia”.,
rumor: myopia and aging can offset each other. If you have a little myopia when you are young, you won’t get presbyopia when you are old.
truth: if you get myopia, you won’t be old when you are old? Of course not. To make this clear, we must first explain the working principle of the eyes and what is myopia, hyperopia and presbyopia.
and
eyes are a camera. In fact, comparing eyes to cameras is really an injustice to the eyes. Eyes are more precise than cameras, but a comparison between the two can make it easier for us to understand the problems of myopia, hyperopia and presbyopia. Like the camera, the eye can also be divided into two parts according to its function. The front cornea, aqueous humor, lens and vitreous are equivalent to the lens group of the camera and belong to the refractive system; The back retina is equivalent to the film or CCD of the camera and belongs to the photosensitive system. The refractive system is actually like a lens, which focuses the images of the wide world on the small retina. The important characteristic of
and
refractive system is refractive power. The greater the refractive power, the stronger the ability to focus the line. The cornea has the largest refractive power in the refractive system, about more than 4000 degrees. But the cornea is a “fixed focus lens”, and the refractive power cannot be changed. The refractive power of the lens is slightly inferior to that of the cornea, about less than 2000 degrees. However, by changing the shape of the lens, the refractive power can be adjusted by more than 1000 degrees, just like the optical zoom function of a digital camera. The combination of cornea and lens constitutes almost all the refractive power of the eye. Through them, the eyes can completely shrink a building dozens of meters high and project it onto the retina of several square centimeters.
lens regulates refractive power in a very subtle way. There is a circle of ciliary muscle around the lens, which is connected with the lens through small ligaments. The ciliary muscle and lens compete with each other at ordinary times. When the ciliary muscle is relaxed, it will pull around and flatten and thin the lens. In this way, the degree of the lens will be reduced by hundreds of degrees, and you can have a panoramic view of things in the distance; When the ciliary muscle is tense, the lens will return to its natural state, become round, thicker and have greater refractive power. In this way, you can improve the resolution by looking at things near you. In other words, the tighter the ciliary muscle, the looser the lens and the greater the refractive power. The more suitable it is to see small objects and see more clearly; The more relaxed the ciliary muscle is, the more tense the lens is, and the smaller the refractive power is. The more suitable it is to see a large scene and the larger the range it can see. The eyes can zoom, and the refractive ability can be adjusted according to the distance of the object, which is realized by the competition between the two brothers of ciliary muscle and lens.
why can you get myopia?
if you read books and computers for a long time, your ciliary muscles will often be in a state of tension and gradually adaptRumor cracked. People can not be short-sighted and farsighted, but they can’t escape presbyopia. The pathogenesis of myopia and presbyopia can not offset each other, so at the age of presbyopia symptoms, you may even need a pair of myopia and presbyopic glasses.