What is the equivalent of 4 9 in vision? 15

。The visual acuity comparison table is as follows:

When checking distance vision, the examination distance should be 5 meters, the height of the eye chart should be parallel to the eye of the examinee with the visual target or logarithmic eye chart, and the illumination should be appropriate. Visual acuity is generally checked first on the right side and then on the left side, with each eye being done separately. When examining one eye, the other eye can be covered with an eye-covering spoon.

The person being examined must have their eyes wide open and must not squint, squint or tilt their head.

When inspecting, point to the optoscope from top to bottom, and if correct, then point to the next line of optoscope. The recognition speed averages 3-5 seconds per word. Record the exact visual acuity value next to the last line of the optoscope.

It is equivalent to the previous one, with 50 degrees of myopia, and you don't need to look at the distance, you can do without glasses.

Vision indicates that there is mild myopia, about 50 to 75 degrees to wear, if it is false, you don't have to wear it, it will be good after a period of adjustment, if you need to work, don't wear it often, if it's a student, then you have to keep it don't deepen, if your vision has decreased, you must wear it.

It is; It is;

And so on, yes.

But yes, yes, yes.

What kind of sports are suitable for children's astigmatism eyes, and life is happy and learning is good.

It is usually said that "it is eyesight, that is, the number represented by the first few rows of the international standard eye chart."

And "200 degrees" and the like refer to the diopter, which is the reciprocal of the focal length f of the diopter system, and the relationship between the "degree" and the diopter when we wear glasses is: 1 diopter 100 degrees.

However, there is no conversion formula between visual acuity and power, because visual acuity and power are not proportional, for example, if someone has a myopia of 800 degrees, they can see it when they look at the distance vision chart, while another person has a myopia of 300 degrees, and they can only see it when they look at the distance vision chart.

There is no direct link between visual acuity and prescription.

The standard visual acuity detected by the international standard eye chart actually refers to the low visual acuity that does not reach the standard visual acuity, but it does not mean the corresponding myopia, farsightedness, and astigmatism. Refractive errors can occur in the human eye, mainly including myopia, farsightedness and astigmatism. Depending on the degree of refractive error, there may be differences in the level of vision examination.

Some people, for example, have 200 degrees of myopia, and may not even be able to see their vision, while some people are 200 degrees of myopia, but they can see standard vision, so it is not possible to match the refraction power of refraction. Therefore, the specific refractive power needs to be determined by formal optometry in the hospital.

The eyesight is this line on the eye chart.

The normal vision of the eye should be above, so if there is vision loss, it is necessary to complete the relevant examinations as soon as possible to understand the specific cause of vision loss. Through visual acuity examination, optometry examination, intraocular pressure examination, and fundus examination, we can have a preliminary understanding of the causes of vision loss.

Optometry can tell if there is refractive error, slit lamp test can check for ocular surface disease or cataracts, intraocular pressure test can check for glaucoma, and fundus examination is mainly to determine whether glaucoma is present.

It's on a five-point scale.

The so-called visual acuity refers to distance vision and is central vision, static vision, which reflects the function of the macula, the most sensitive part of the retina, and distance vision examination is usually performed with an eye chart.

1. Central vision: that is, people usually look at the visual acuity chart to determine the visual acuity.

2. Peripheral vision: When the eye fixes on a certain target, the range that can be seen in the non-fixation area is large or small.