The refractive index of a lens is determined by the material selected for the discount eyeglasses online lens. In the case where the center thickness and sheet size are the same, lenses of the same degree and materials with the same refractive index have thinner edges than lenses with lower refractive index.

The price of lenses can be inferred based on the refractive index of the same brand and series. The higher the refractive index, the higher the price.

However, when comparing different brands or different series of the same brand, there is no significant difference in basic optical indicators such as effective light transmittance, wear resistance, and anti-fouling (anti-static, oil resistant, waterproof, etc.). Only under the same quality conditions can the price be compared between cheap and expensive.

The quality of individual materials for manufacturing the cheapest eyeglasses online lenses, the quality of lens molds, the level of coating and production processing technology, quality control capabilities, and quality stability.

It is worth noting that when choosing lenses, the higher the refractive index, the better. On the contrary, visually speaking, the higher the refractive index, the better.

The discount prescription glasses fitting cycle is very long, so in the actual fitting process, it is necessary to systematically consider and comprehensively consider issues such as visual quality, aesthetics, and wearing comfort, to achieve the best possible effect when worn for a long time.

It is not recommended to do secondary processing on the lenses, which is to grind down the larger ones and fit them on the smaller frame. If the processing technology is not high enough, there will be a problem of excessive pupil distance or (and) pupil height error, and the probability is not low.