What does it mean to not reverse? Since I was asked this question, I want to talk about myopia first. The human eye is like a camera, the front of the camera is the lens and aperture, the back is the imaging processor; the pupil of the human eye and the cornea and crystal are like the lens and aperture, and the retina is the imaging processor. It should be understood that if the focal length of the lens is not on the processor, (Albes optics) then the imaging is not clear; in the same situation, if the focus of the cornea and the crystal is not on the retina, it is not clear what to see, it may be Myopia is farsighted or astigmatic.
Under what circumstances is myopia, if parallel light is focused on the front of the retina through the crystal, we are called myopia. There are actually two situations. The first is that the refractive power of the cornea and the crystal is too strong, and the focus is too far forward. The second case is that the retina is too far away, and the "screen" is too far behind. Because the eye is a "camera" that can be zoomed, the blur caused by excessive crystal zoom is generally what we often call "pseudo myopia", so pseudomyopia can be recovered by drugs or rest. But if it is true myopia, it is the second case. (Albe optics) The retina is too far from the focus, and the focus is on the front of the retina, which produces myopia. When we are young, the eyeballs are small. As the growth and development progresses, the eyeballs will grow and grow longer, so the retina will only get farther and farther away from the focus, and the degree of myopia will become higher and higher. Until the age of 18, growth and development basically stopped, the length of the eyeball no longer changed, it will slowly stabilize. However, if you have developed a high myopia of more than 600 degrees before the age of 18, the eye axis may continue to grow longer and the degree will continue to increase. Conversely, if it is a hyperopia, because the focus is on the back of the retina, as the eyeball grows, the degree will become smaller and smaller, and even achieve the effect of "healing".