Amblyopia is a disease in which vision does not reach normal even with any glasses. Through early detection, optometry, active intervention and therapeutic training, it is almost always possible to obtain the desired corrected visual acuity. If you maintain your vision for 3 years, you can declare that your amblyopia is cured. However, due to the pathogenesis of amblyopia itself and the treatment process such as masking or reducing the degree of hyperopia in order to improve vision as soon as possible, which affects the formation or perfection of simultaneous vision in both eyes, many children who seem to have good vision already have only one-third of normal visual function. So, are these children cured of amblyopia? Let’s just say it is far from it. Studio Ophthalmology Xu Yuan Why is the vision good, but the visual function is far from normal? This starts with the tertiary visual function of the human eye. The human eye, to eye to see the outside world, first of all, the size, shape, color, brightness, location and other characteristics of each luminous point on the object in the eye imaging. Just like a camera, need accurate focus, the right aperture, shutter speed and other conditions are good, in order to take an ideal photo. Such a good photo does not yet reach the first-class vision function of the human eye. Both eyes can take a picture, and can be put on a screen at the same time, to do simultaneous vision, is the first level of vision function of the human eye. This is also the basis of the last two levels of vision function. Inadequate primary visual function affects secondary and tertiary visual function. If our eyes only have primary function, first of all, they are too tired, and more importantly, they lack the ability to judge distance and depth perception. If the two eyes work well together, like two people working in tandem, they will not be too tired. If these two people work together, interfere with each other, or each doing their own work, fatigue will come faster than others, but also cause damage. Both eyes interfere with each other, not only easy to visual fatigue, but also easy to turn off the other switch for a long time and can not open again. Whether only one eye or two eyes alternately turn off the switch, the end result is to wear glasses can not improve vision, which is the pathogenesis of amblyopia. Each eye does its own work, and the first hope is that the other does not engage, often turning off the other’s switch. After the switch is turned off, the electrical activity of the posterior neurons is affected, leading directly to vision loss, which over time is amblyopia. The brain is able to fuse the imaging of the two eyes in order for the two eyes to work together. The ability to see far and close together indicates sound secondary vision function. It can be said that the soundness of the secondary visual function is also affecting the stability of the primary visual function. Some children do not form simultaneous eye habits from an early age, and none of the primary visual functions are sound enough. Just selective use of one eye is not necessarily amblyopic. Some amblyopes get used to selective monocular use and give up their primary visual function during amblyopia treatment. These amblyopias are not necessarily repeated even after the vision is improved by treatment. The good vision obtained is able to be maintained for three years and does not recur. It seems that the amblyopia problem is solved in these children, but the visual fatigue caused by the inability of the two eyes to cooperate may also cause a series of problems. For example, problems with high eye pressure, problems with increasing myopia, etc. The inability of both eyes to cooperate or to cooperate well in a certain position is a problem of second level visual function. More importantly, stereopsis is the highest level of visual function in the human eye – the third level. What is stereopsis? Why is it more important? Earlier, the human eye was compared to a camera. In fact, the eye is more simple than the function of the camera, neither shutter, nor film, at best, a monitor. The information collected is transmitted to the brain in real time, and the information enters the brain and is processed to virtually create an outside space in the brain, and the brain is the key part to reproduce the outside space. The monitor is generally only one, it can only transmit a plane information into the brain, presenting a plane image. In this image, only through the surrounding reference points, or the size of the object contrast to determine the distance from the target monitor. The vast majority of animals, in the course of evolution, have chosen to have two eyes. Evolution to primates, both eyes are facing directly in front, which is ready for a timely and accurate judgment of the distance. Humans need more accurate judgment and manipulation, which requires more demanding information from both eyes. There are only extremely subtle differences between the two eyes when looking at distant objects, but the brain can use these differences in the process of information processing to virtually create a space that is as consistent as possible with the real space. The ability to achieve this is known as sound distant stereopsis. The closer the virtual is to the real, the more accurate the judgment will be. The more accurate and rapid the judgment, the less chance of operational error. If the far stereo vision function is not sound enough, only one eye plane imaging can be selected, when the person is driving a high-speed car, found in front of the target, it will not be able to accurately judge the distance in time, but need to refer to the surrounding objects or according to the size to infer the distance, and so on to make a judgment is already too late. Such a person driving, the chance of problems than normal people much more. In the United States, there are statistics that people with inadequate stereo vision have a driving accident rate that is 5 to 6 times higher than normal. When both eyes look close at the same time, the imaging of the two eyes will look much worse. The left eye sees more from the left side of an object and the right eye sees more from the right side of the object. However, such images are transmitted to the brain at the same time, and the brain can also virtualize the two images to produce an object that is consistent with the target of gaze. The ability to perform this function is called near-stereoscopic soundness. The closer the shape and position of this virtual object is to the real one, the more accurate the judgment will be, and the stronger the actual operation ability will be. We often see that some people are exceptionally good at fine manipulation, while others have difficulty with training, precisely because of this prerequisite. Far stereo vision is not sound enough, you can not drive, at least not as a professional driver. Near stereopsis is not sound enough, you lose the ability to work accurately and in a timely manner, at least not as a surgeon. When a child has amblyopia, the parents go through a lot of trouble and the child’s vision improves. It is important to know while being happy: timely establishment and improvement of the child’s secondary and tertiary visual functions. The opportunity is just when the binocular vision has reached normal, and when it is maintained for three years without dropping, and when the child is used to the choice of using one eye, and even the primary visual function is not sound enough, it is the same as giving up the secondary visual function completely. The chances of establishing tertiary visual function again at this time are greatly reduced. Medical professionals involved in strabismus treatment are urged to note that perfect tertiary visual function is the ultimate goal of amblyopia cure. Parents are reminded that amblyopia is far from being cured when visual acuity is improved.