Because.
Myopia, farsightedness, presbyopia, astigmatism, etc.
Vision loss caused by refractive errors.
Normal vision is achieved by means of correction.
It's called vision correction.
Corrected visual acuity is relative to uncorrected visual acuity.
Unaided vision is your actual vision.
Correction of vision. It is the visual acuity obtained by correcting the refractive error with glasses.
For example, the unaided visual acuity is 08
Corrected visual acuity after wearing glasses15
Corrected vision.
Not the same as unaided vision.
It is higher than the naked eye.
For mild to moderate myopia.
Generally up to 10 basic requirements.
The key to correcting vision lies in the word "positive".
Myopia is usually caused by refractive error.
Vision correction is performed to see clearly.
By wearing ordinary eyeglasses.
Achieve clear vision.
This is the most basic requirement.
A general optician's shop will suffice.
But. After vision correction.
Wear regular glasses.
Myopia will also deepen.
What to do?
This is where "vision correction" comes in.
Vision correction. It is on the basis of vision correction.
Further efforts to prevent myopia progression.
Children and adolescents in their development.
Wear plain glasses.
The average increase in myopia is 75-100 degrees per year.
If you don't intervene.
When the child becomes an adult.
There is a high probability that it will become.
Patients with high or even very high myopia.
It can bring a lot of eye diseases.
It will even be passed on to the next generation.
This also illustrates the need for "vision correction".
Methods of vision correction.
Usually, there is. Wear.
Orthokeratology lenses, defocus myopia prevention and control lenses.
and surgery**, etc.
At the same time, it is supplemented with atropine.
and vision training.
Achieve the purpose of myopia control.
Teenagers wearing orthokeratology lenses.
On average, myopia increases by about 25 degrees per year.
The effect is obvious. 
Although not yet.
* A good way to be nearsighted.
However, the degree of myopia is further deepened.
Still a lot of progress has been made.