Frames and lenses are two important components of a pair of glasses. For a wide variety of lenses, how do you introduce them so that customers can see your lenses at a glance? You can start with the following aspects:
The quality of the substrate determines the durability of the lens used and the reliability of the coating. The good substrate is clear and translucent, and it takes a long time to use and is not easy to turn yellow; while some lenses turn yellow in a short time, and even the coating peels off. Good lenses have no scratches, scratches, rough surface, pitting, and the lens is obliquely observed in the light, and the finish is extremely high. There are no spots, stones, stripes, bubbles, cracks inside the lens, and the light is bright.
The mass-produced lenses are divided into different grades due to the difference in internal quality, and the prices of superior products and second-class products vary greatly.
The higher the refractive index of the lens, the thinner the thickness and the higher the price.
Coating and UV protection
Resin sheets can be hardened (scratch resistant), anti-reflective, anti-static, dust-proof, waterproof, etc. Up to a dozen layers of coating treatment, different coating treatments have different effects, if the coating process is reduced, the quality of the lens It will be greatly discounted. Similarly, if a non-UV-resistant lens is worn as a UV-resistant lens, it is very harmful to the eyes. Excessive absorption of ultraviolet light by the human eye can easily cause various eye diseases such as photokeratitis, cataract, and macular degeneration.
Brand differences lead to differences in quality and price. The quality of the lens is directly reflected in the brand of the lens. Brand-name lenses are of good quality and stable. Domestic such as Mingyue, Tianhong, Wanxin, etc., such as Essilor, Zeiss, etc. are relatively well-known.
Test lens transparency and optical uniformity
Hand-held lens, and about 30 cm away from the eye, through the lens to observe the distant scene, if the scene is clear and no deformation, and there is no scene jumping when moving the lens slowly, it shows that the transparency and optical uniformity of the lens are better.
No feeling when wearing
Do not dizzy, observe objects are not blurred, no deformation. When buying, hold the glasses in your hand, use a single eye to see the distant objects, shake the lens up and down, and the distant objects should not move.
High-quality lenses that are 100% resistant to UV A-B rays provide the most effective UV protection for those wearing glasses.