TEL.

+0086-577-86192787
18857755077

FAX.

+0086-577-86732601

EMAIL.

hengzi@hengziglasses.com

Wenzhou Wanrun glasses manufacturer tells you how to configure glasses

First of all, it is recommended to choose a formal optometry institution for optometry, whether it is the first time to match glasses or change glasses. Teenagers under the age of 18 also need mydriatic optometry to determine whether they are true myopia

  • Details
  First of all, it is recommended to choose a formal optometry institution for optometry, whether it is the first time to match glasses or change glasses. Teenagers under the age of 18 also need mydriatic optometry to determine whether they are true myopia or false myopia.

  Myopia is generally divided into pseudomyopia, true myopia and mixed myopia. Pseudomyopia is mainly due to the continuous contraction and spasm of ciliary muscle and the increase of lens thickness caused by overuse. Like true myopia, pseudomyopia shows decreased far vision and good near vision. Generally, it decreases and recovers within one week to one to two months. However, if it is not relieved in time, it will also develop into real myopia, that is, permanent myopia.


  Mydriatic optometry is mainly used to distinguish true and false myopia. In technical terms, mydriatic optometry relaxes the ciliary muscles of the eyes and removes the components of pseudomyopia through ciliary muscle paralysis. The diopter obtained in this state is the most true and accurate. Because cycloplegic agents are usually prescription drugs, this optometry method can only be carried out in hospitals, while optical shops often can only carry out obvious optometry, and the data obtained are not necessarily accurate. Glasses with inaccurate data often cannot be effectively corrected, which will lead to eye fatigue and even vision loss.




  It should be noted that after mydriatic optometry, the pupil will expand, the light entering the eye will increase, and the optometry time will be very long, so more attention should be paid to the protection of children's eyes at thistime.We generally do not recommend children to wear glasses with metal frames and glass lenses, because many children have strong curiosity. Metal frames and glass lenses are easy to break and fragile, which is relatively unsafe. Therefore, we generally choose relatively safe, lightweight and durable frames such as plate type and TR90, as well as plastic resin lens glasses. Relatively speaking, children's glasses don't need to add too many additional functions when choosing, and they mainly focus on the quality of glasses frames and lenses.


  In the lens part, three parameters need to be considered: refractive index, Abbe number and sphere.Generally speaking, the refractive index is: when the thickness of the center of the lens is the same, the higher the refractive index, the thinner the edge of the lens. In other words, the higher the refractive index, the thinner the lens. But this does not mean that we need to pursue high refractive index.


  Abbe number refers to the dispersion coefficient, which is only the dispersion of seven colors of light scattered by sunlight after passing through the prism. The higher the Abbe number, the smaller the dispersion, in other words, the clearer. Interestingly, it is often difficult to have high refractive index and high Abbe number at the same time, because the thin edge of a high refractive index lens will also lead to greater dispersion. Therefore, we only need to choose a suitable range of refractive index, and for low myopia patients, it is not necessary to choose high refractive index lenses. Of course, patients with severe myopia can also consider using lenses with high refractive index and high Abbe number, but the price is often very high.









Spherical and aspheric lenses are also common concepts. When light passes through a spherical lens, the focus is different, which will produce aberration. The actual feeling caused by this distortion is that the edge of the visual object is distorted, and it is easy to get dizzy after wearing it for a long time, so we should pay more attention to fatigue. The aspheric lens is cut to ensure that the focus of light passing through the lens is the same and the image will not be distorted. In addition, the lens will be thinner and lighter, and the glasses will be more comfortable to wear. However, due to the cost, most lenses are basically single-sided aspheric. The price of double-sided aspheric surface is too high to be considered when matching glasses.
Copyright (c) 2018-2022 WANRAY(HENGZI) All Rights Reserved. 浙ICP备2022026496号-1