The yellow index means that the larger the eyeglass online lens, the more yellow it becomes. Generally, due to the requirement of anti-UV or anti-blue light, yellow UV or blue light absorbing materials are added to the lens.

In order to prevent the lens from turning yellow, blue dye is usually added, but blue dye can also affect the light transmittance. Therefore, how to reduce the yellow index without reducing the light transmittance as much as possible depends on the level of craftsmanship.

Turbidity is a parameter that measures the occurrence of large-angle light scattering inside the lens, simply put, it is whether the lens substrate is clear enough.

The difference in reflection is also very large, the lower the reflection, the higher the transmittance. This is a relatively simple method for determining transmittance.

The factors affecting transmittance include reflection, scattering, and absorption of the eyeglass online lens, with reflection having the greatest impact. A feasible way to select lenses is to look at the reflection of the lens under the lamp tube. The brighter the reflection, the lower the transmittance of the lens.

Optical lenses are an important component of optical systems and an essential knowledge in optical engineering. A lens is an optical component made of materials that can transmit a specified spectrum. Generally, optical glass is used for visible and near-infrared spectra, and crystal materials are used for mid-infrared spectra. Lens technology can be widely applied to various types of optical instruments.

The optical lens generally refers to a refractive mirror with a spherical refractive surface. Some are composed of two spherical surfaces, while others are composed of one spherical surface and one plane. Due to different orientations and characteristics, optical lenses used alone or in combination will produce different effects.