Resin discountglasses lenses are lighter, safer, and have light transmittance similar to glass lenses, but thicker compared to glass lenses. PC lenses are lighter than ordinary fiber lenses and have higher impact resistance than resin lenses. Therefore, it is often recommended to choose PC lenses for sports glasses.
There are different types of refractive indices for lenses, such as 1.5, 1.56, 1.59, 1.60, 1.67, 1.71, 1.74, 1.76, etc. How to choose the refractive index of a lens depends on prescription parameters, frame size, lens function, lens parameters, and specific wearing requirements.
Under the same conditions, the higher the refractive index, the thinner the discountglasses lens; The edges of lenses with the same refractive index and material are thinner than those with lower refractive index. For patients with high refractive index, high refractive index lenses can mainly improve thickness and emphasize aesthetics.
The Abbe number corresponding to different refractive index lenses reflects the imaging quality of the discountglasses lens. The higher the Abbe number, the smaller the dispersion of the lens, and the better the imaging quality. Generally, the Abbe number of a lens is between 30-60, and the larger the better.
Strong dispersion can cause a prism effect, leading to dizziness, blurred vision, and brain swelling. Of course, the larger the frame, the greater the prism effect. A frame with a smaller height will be comfortable.
But in fact, the refractive index is inversely proportional to the Abbe number, the higher the refractive index, the lower the corresponding Abbe number. So we cannot blindly pursue high refractive index, because high refractive index will inevitably sacrifice imaging quality.
Plated with a certain thickness of single-layer or multi-layer optical film, the lens obtains some new and excellent properties that were not originally possessed, to improve the ability of the lens to reflect light and enhance or reduce the transmission of light.