The degree is the degree given to us during optometry, but cheap eyeglasses near me lenses are divided into spherical, aspherical, and double-sided aspherical lenses. For individuals with high myopia or hyperopia who wear glasses, the deformation around the spherical lens is more pronounced. Therefore, to reduce deformation, nonspherical lenses are produced.
What is an aspherical lens? It is a lens with a lower degree of curvature than the center. If the degree is low, the deformation will be smaller. So when we wear glasses, please ask to point the pupil height and measure the distance between the eyes.
The higher the refractive index, the thinner the lens, but correspondingly, the higher the price. For low degree cheap eyeglasses near me, are already relatively thin, so there is no need to choose high folding lenses. The Abbe number is the dispersion coefficient. The higher the Abbe number, the smaller the dispersion, and the clearer the visibility.
Natural light is composed of seven colors of light: red, orange, yellow, green, blue, blue, and purple. The same material has different abilities to deflect light of different colors (wavelengths).
When the deflection caused by different colors of light is different, dispersion will occur, and there will be rainbow patterns around the lens. The clarity of wearing this type of lens will naturally decrease. In addition, the higher the refractive index, the generally lower the Abbe number. When choosing, we should pay attention to discrimination eyeglass online.
It is incorrect to determine the suitability of refractive index solely based on the degree, and the height may not necessarily be suitable for high refractive index lenses. Not to mention that the degree and frame are the same as the old glasses, but the refractive index has changed. Any new glasses may have slight or significant changes in their matching parameters.
