What is the difference between refraction and myopia?

Those who wear myopia glasses usually know the degree of their myopia, such as 300 to 400 degrees. In contrast, many people do not know what the refractive power of the eye means. In fact, the refractive power is also an indicator for evaluating a person's vision. There are currently two main methods for detecting refractive power, namely the retinal refractor method and the automatic ophthalmometer detection method. The following introduces the difference between refractive power and myopia.

The difference between refraction and myopia:

Conversion relationship: 1.00D=100 degrees (the standard writing method is 1.00D with 2 decimal places)

If you are nearsighted:

300 diopter is -3.00D

400 diopter is -4.00D

The diopter between 300 and 400 is -3.00D~-4.00D

Being an ophthalmologist is an absolutely standard answer. Good luck.

Note: If you have farsightedness, just change the - to +.

Myopia diopter is the unit of refractive power, expressed in D, which means that when parallel light passes through the refractive material and the focus is at 1m, the refractive power of the refractive material is 1 diopter or 1D.

In terms of lenses, it refers to the unit of lens power. For example, if the focal length of a lens is 1m, the refractive power of this lens is 1D diopter and focal length or reaction.

A degree between 300-400 degrees is considered moderate myopia. Generally, what you need to fill in is your visual acuity, which is the corresponding value on the vision chart. 300-400 degrees corresponds to 4.4-4.5 on the new eye chart and 0.25-0.3 on the old eye chart.

Moderate myopia in primary school students needs to be treated in time, otherwise the degree will continue to increase with age. Generally speaking, you need to wear glasses and take Lejing vision nutrients orally, two packets a day, with warm water. If you take it for a period of time, the myopia will gradually decrease and the vision will improve. In addition, if you correct bad eye habits, your eyesight will get better and better. It will not affect your future life and study.

Refraction generally refers to the change in the optical path of parallel light rays. For the eye, the most direct change in refraction is reflected in the curvature of the lens. The closer the object is, the greater the curvature of the lens, which makes adjustment more laborious, and is reflected in the feeling of eye fatigue, which is equivalent to the symptom of reading for too long at close range. The lens is the most direct adjustment structure for the human eye to see far and near, which is equivalent to a convex lens. It is different from the convex lens in physics in that it is adjustable, that is, its curvature can be adjusted according to one's own needs to change the distance of the focus to achieve the purpose of seeing objects clearly.

There are certain requirements for determining the degree. Generally, it is based on the lowest degree at which people can see the 1.0 position on the vision chart at 5 meters. It is only an indicator of the specific curvature of a state in which people can see a specified object clearly. Changing the position will have different requirements and responses, so there is no need to wear glasses all the time. It only changes the refractive power that people need to see clearly at about 5 meters.