The resin lenses currently on the market are CR-39 based lenses. In general, the UV protection of 1.499 ordinary resin lenses is very low (320um), but other lenses above 1.56 have UV protection (380um). If it is 1.56 plus film, it is possible to protect against UV up to 400um. But if it is 1.499 ordinary plus film UV protection is also very poor. Here I also want to tell you that the raw material of CR-39 itself does not have much UV protection, but the UV powder is added when the lens is infused. The UV protection ability of the lens is determined by how much UV powder is added. There is another type of lens that can be said to be 100% UV-protective, the PC lens. For the identification of lenses, professionally, it depends on the quality of the image, transmission, Abbe number, lens design, refractive index, quality of the coating, etc. From the customer’s point of view, it is to see whether the base color is purely transparent, whether the film addition is uniform, whether the reflection of the film addition layer is consistent, and whether the prescription is precisely high. Currently there are four plus film color on the market, gold, green, red, purple (blue) these four, I recommend that you use the green film, the other film color is just to look good, is not very good for the eyes with science, green film on the human eye the smallest impact, the highest light transmission rate. For the said to look at the sun seems to have a layer of purple, is due to chromatic aberration, normal ah, more than 1.56 lenses, can be said to be UV protection, but Abbe number is a little lower, so there is a very small rainbow vision phenomenon.