How to distinguish the pros and cons of PC lenses?

How to distinguish the quality of PC lens? Generally speaking, inferior PC lenses are produced by underground factories without a license, the equipment is simple, and the cost is very low, so the price is particularly low. In terms of PC lens materials, the resin matrix of inferior lenses is impure, which can cause distortion or vertigo of vision. The dispersion effect is large, which can easily cause visual fatigue. Poor impact resistance and easy to break. The light transmittance is relatively low, and the light distribution is uneven. Refractive index can not achieve the effect of its promotion, it will exaggerate the ultra-thin lens.

Poor-quality PC lenses have poor surface treatment and no hardening and anti-flowering functions. Poor quality PC lens coating technology is poor, easy to peel off. The film layer can not meet the requirements, the anti-reflection ability is low, and there are no main functions such as waterproof, anti-fouling and anti-fog. In terms of PC lens frame materials, the metal smelting of inferior glasses is poor, with low purity, many impurities, and even harmful radioactive elements to the head. It has a large specific gravity and has a strong compression effect on the nose bridge, which is not conducive to the development of the nose bridge of adolescents and children. Poor elasticity, brittle and easy to crack. Poor appearance gloss and color, poor corrosion resistance, easy to rust, easy to change color. In addition, it also has a great effect on the skin, is easy to cause allergies, and is soft and deformable. Regarding the processing technology of PC lens frames, the inferior glasses have rough appearance and dull color. The electroplating technology department is good and easy to discolor.

Poor quality PC lens welding technology is poor, the welding point is not strong, easy to desolder. Hinge and thread are easily damaged. The assembly of inferior PC lenses also fails to meet the national quality standards. The optical center of the double spectacle lens is high and low, left or right, inaccurate interpupillary distance, inaccurate astigmatism axis position, etc., will form an inappropriate prism effect, affecting normal visual function.

Hold the PC lens, and observe the distant scene through the lens about 30 cm away from the eye. If the scene is clear and undistorted, and there is no scene jump when the lens is moved slowly, it means that the PC lens has good transparency and optical uniformity. .