What is the prescription of glasses for myopia, and how to calculate the prescription of glasses

In medicine, myopia is divided into three types according to the diopter (d), which is the unit of refractive power, among which the diopter of high myopia is above, that is, the myopia is greater than 600 degrees. What is the degree of high myopia? High myopia refers to refractive error with a myopia degree greater than 600 degrees, accompanied by degenerative lesions such as axial elongation and fundus retinal and choroidal atrophy.

Less than three is mildly myopia, while between three hundred and six is moderately myopia. If you want to consider laser correction of myopia**, it is recommended to come to the hospital to check the corneal thickness and corneal flexion rate and other eye conditions, and laser surgery is usually recommended to preserve more corneal thickness and improve visual quality. The pathogenesis, pathogenesis and prevention of high myopia are different from those of general myopia.

In China, high myopia is an autosomal recessive inheritance. It is manifested by the onset of myopia in the school-age (pre) stage of children, the progressive increase in myopia, and the worsening of fundus retinal choroidal lesions year by year, resulting in many serious complications. Therefore, high myopia is also known as pathological myopia, malignant myopia, degenerative myopia, progressive myopia and genetic myopia.

Causes of high myopia With the development of society, the knowledge we need is constantly growing, the probability of using eyes is greatly improved, and the probability of myopia is also increasing. Myopia is divided into high myopia and common myopia, and the general degree of common myopia is less than 600 degrees. Myopia is a polygenic inheritance, that is, patients have multiple pathogenic genes, but there are environmental factors, and common myopia is more obvious.

Environmental factors include poor lighting, poor reading and work habits, such as long hours of reading and close work, and a constant state of tension and contraction of the regulatory muscles of the eye, which in turn weakens the ability to accommodate, resulting in myopia. But under the same conditions, not all people develop myopia, and some people with myopia do not do near work or rarely read books and newspapers. So it's the result of the interaction between the two.

High myopia is thought to be caused by autosomal recessive inheritance. For high myopia of 600 degrees, even if it is high myopia, the vision of the high myopia eye is low and difficult to correct, and wearing fully corrected glasses is often intolerable) so the glasses should be corrected at a low level to strive for some improvement in vision. There are many serious complications in height, and care should be taken to protect from **.

Refractive data with a negative sign is myopia.

Power of glasses = diopter power x 100. Diopter is the unit of diopter power, expressed in d, which refers to the refractive power of parallel rays passing through the refractive substance, and the diopter power of the refractive substance is 1 diopter or 1d when the focus is 1m. Diopters include retinal ophthalmoscopy and autorefractor.

1 diopter or 1d is equal to what is often said to be 100 degrees.

The function of the eye to refract light is called refraction, and the ability to refractive light is expressed in optical power, which is called diopter.

If the refractive power of the eye is incorrect and cannot be accurately imaged in the retina, it is a vision defect and usually requires glasses.

The stronger the refractive power, the shorter the focal length. The focal length of the lens for 2D diopter power is 1 2m or 50cm. For example, the focal length of 5D diopter power is 20cm.

Generally, it is 500 degrees of myopia, and the farthest distance that can be seen with the naked eye is only 20 centimeters.

Logarithmic visual acuity, equivalent to decimal point vision, myopia is about the reciprocal of decimal point visual acuity multiplied by 100, called 250 degrees. Visual acuity is not completely consistent with myopia, because the intensity of eye accommodation is different, and the visual acuity should be 100 degrees or 300 degrees. To make a clear diagnosis, dilated refraction is required, and accurate myopia can be obtained by using cycloplegic agents, such as atropine eye drops or tobiamide eye drops, to paralyze the ciliary muscle and relieve the spasm of the ciliary muscle.

When the first myopia occurs, it is necessary to diagnose true or false myopia, it is recommended that you go to the optical center for examination, and then you can determine the degree of myopia, if you want to know how many degrees of ten centimeters of your eyes are, you must go to the hospital for dilated refraction, because it is difficult to infer a very accurate degree through this specific symptom, and it is difficult to infer a specific naked eye vision through a specific degree, so if you want to know how many degrees, you must go to the hospital for dilated eye refraction.

All the means of improving the patient's vision are called vision correction methods, and the common methods are:

1. Wear appropriate glasses.

2. Increase outdoor activities.

3. Use low-concentration drugs, such as atropine, etc.

4. Teenagers can choose to wear orthokeratology lenses (OK lenses).