What is a multifocal progressive lens? The lens provide a gradual transition in strength from bottom to top. Progressive multifocal glasses are suitable for reading and looking at distant objects without frequent picking. It have 3 degrees in one pair of glasses. That allows you to do close-up work (like reading and writing), middle-distance work (like using computer), or distance viewing (like driving and walking). It allows people to see clearly at different distances, just one pair of eyeglasses for everything. What is Blue Light? Blue light has a short wavelength and is likely to scatter, causing fatigue of the ciliary muscles, which are the adjusting muscles that adjust the lens, and may cause eye strain. Blue light can cause a wide range of risks including eye strain, sleep disorders, damage to the retina, dry eyes, stiff shoulders, and headaches. For those who operate smartphones and PCs or watch TV, it is recommended to take measures immediately with blue light blocking glasses. SIGVAN Progressive Multifocal Blue Light Blocking Reading Glasses High manufacturing quality, material lightweight and durability. Metal spring hinges help glasses adapt to face,built-in stainless. Convenient Set of 4 means you\'ll have a pair handy wherever you are. Keep a pair in your favorite reading spots. Block blue light, suitable for people who use mobile phones and computers for a long time. Size: Lens width: 53mm/2.08in Lens height: 42mm/1.65in Bridge:19mm/0.74in Arm: 140mm/5.51in Frame width: 140mm/5.51in Material:Plastic, which has the characteristics of super lightness, abrasion resistance low friction coefficient and so on. Package includes: 4 x Progressive Multifocal Blue Light Blocking Reading Glasses 4 x Eyeglass Pouch 1 x Cleaning cloth If you have any problems with our items or services, please feel free to contact us. We will do our best to solve any problems and provide you with the best customer services. Thank you so much for support us!