Do highly educated friends feel this way? Every time I change a pair of glasses, I find that the degree of the lens does not change, but the thickness of the lens is different. Some are thin, some are thick and ugly. In fact, there are many reasons.

     Myopic lens is a concave lens, which is characterized by thin middle and thick edge. The thicker the edge, the higher the degree. The thicker the edge of the lens. When your degree is higher, the edge of the lens will be thicker, just like the bottom of a wine bottle. It will press the red and deep marks on the left and right sides of the nose. To avoid this situation, we should pay attention to the following issues when matching glasses.

Lens selection for high myopia

     First: For high myopia glasses, it is recommended to use small frames. The higher the degree, the closer the lens is to the edge. It is not recommended to select larger frames. When the degree exceeds 600 degrees, we usually call it high myopia. These patients try to choose small frames when choosing glasses. The small frame can cut more parts of the edge of the lens and leave the lens in the central area, making the processed lens thinner, lighter and more beautiful.

     Second, select a high refractive index and aspheric lens. The thickness of the lens is related to the refractive index of the lens. For patients with high myopia, the refractive index of the lens is 1.67/1.67/1.71/1.74. Of course, 1.74 is the thinnest, but the price is very high. You can choose according to your own budget. The spherical and aspheric design of the lens surface will also have a certain degree of thickness change. From the perspective of vision and thickness contrast, aspheric lens is more recommended. Aspheric lens not only makes the image around the thinner lens more realistic.

     Third, the reason for the pupil distance is that everyone's pupil distance is fixed, but some errors may occur when the glasses shop processes glasses. The national allowable error range is generally within 2mm. The higher the degree, the smaller the allowable error. When the error is different, the thickness of the lens will also be affected.

     Fourth: The production factory, the state has strict standards for the central thickness of lenses. However, some factories may adjust the central thickness of the lens to make it thinner, which may cause the lens to break easily. Therefore, thin lenses in particular have potential safety hazards. When purchasing lenses, you must choose lenses from a regular manufacturer. The article comes from the internet. If there is any infringement or violation, please contact us for deletion and correction. Disclaimer: Some resource pictures and text messages of this website come from the network. If your rights and interests are infringed, please notify us in time by email: xsd@66ra.com