First of all, & quot; eyesight & quot;, in short, people's ability to see things clearly, the quality of eyesight is judged by seeing things far and near, good 1.5, 2.0, bad 0.1.
There are many factors affecting visual acuity, such as eye inflammation can cause visual impairment (trachoma, red eye disease, etc.); trauma can also cause visual impairment; lens opacity, vitreous opacity, retinal diseases and other diseases can also cause visual impairment; but most of the visual impairment of adolescent students is related to short-range eye fatigue.
& Quotient; myopic degree & quot; generally refers to diopter, for the eyes, the most direct diopter change is reflected in the degree of lens curvature, the closer the object is, the greater the curvature of the lens, in terms of regulation, the more laborious it is, in response to self-perception is eye fatigue; the lens is equivalent to a convex lens, that is, it can be adjusted according to its own needs. The degree of bending, to change the focus of the distance to achieve the purpose of seeing things.
Simply put, myopia degree refers to the refractive power of cornea, vision refers to the ability of fundus retina imaging, the same degree can have different vision, the same degree can also have different degrees.
Although the higher the degree of the same person in the same period, the worse the visual acuity, but there is no absolute relationship between visual acuity and myopia, more disproportionate. Among the myopic patients, there are 300 degrees of myopia, 0.2 visual acuity meter, 400 degrees of myopia, and 0.2 visual acuity measurement. So, it's just an inspection standard.
Uncorrected vision and diopter are two commonly used indicators to measure visual acuity. There is a certain relationship between them, but not a positive correlation. People who wear glasses for a long time mainly look at things through glasses rather than their own eyes. The adjusting function and visual function of the eyes gradually degenerate, even if the diopter is small, the vision of the eyes is poor; while people who often wear glasses have better adjusting function and visual function, even if the glasses are high, the vision of the eyes will be relatively better.
Therefore, we can often see in life that people who have been wearing 200 degree myopia have less naked vision than those who do not often wear 400 degree myopia glasses.
