The following describes the four kinds of Fake Oakleys Frogskins Sunglasses Cheap for Sale lenses for your criteria:
1, glass lenses
More scratch-resistant glass lens with the lens characteristics than other materials, but the relative weight are more heavy, relatively high refractive index: 1.523 ordinary piece, thin piece: 1.72 or more, up to 2.0. Polymer resin lenses: polymer resin lenses are lighter than glass lenses, impact resistance not broken, but because of its low hardness, it is more prone to scratches than glass.
2, PC lens
There is also a material that is more resistant to impact than the polymer resin, often transparent windows for aviation Cheap Mac Cosmetics Makeup wholesale Outlet equipment, police on masks, and masks astronaut's helmet on, it is only about one tenth of the weight of the glass with the traditional compared resin lens is only half the weight.
PC lenses generally need to add anti-scratch protection film after, in the use of time would be enough to get better, most used in children's glasses, or goggles athletes. PC lenses also have an important feature that PC lens with isolated harmful UV effects, but its disadvantages are also included surface easily scratched.
3, bifocal lenses
Bifocal lenses can be simultaneously corrected distance visual acuity and the last two were mainly for the time required for correction of presbyopia. General bifocal lenses allocated as follows: the upper lens is to see the distance, the lens is used at low use of near point of view, as the near range of the size, depending on the nature of the work to set near by.
Probability is used generally flat top bifocal, they are only a small area at the bottom of the lens as a near point of work, as the periphery of the upper portion of the lens is used with a remote monitor good peripheral vision. The traditional bifocal Tiffany and Co Key Necklace Jewelry Outlet lenses to line bifocal lenses, lens down into two parts by the middle, which is less than half of all lenses used as a near point distance, they provide a better wide near point vision for a long time workers at near point have a better effect, architects, accountants, and other artists who work close to nature, such lenses can reduce the chance of head swinging. Bifocal lenses can also be used in only just read the required correction to the near point, but not in the near point work actually put on glasses to take to win.
4, three-focal lenses
For those in need of vision from the people (usually about from 18 inches to six feet), as far and near in general, the use of these three focal lenses to meet the needs of those people in front of a computer or cash register work for this vision in the distance with special needs, such a vision lenses to meet the needs of his work.
Corrective lenses are also the effects of these comprises a plurality of ranges, the type of lens is different between each piece of the boundary is not obvious from these boundary multifocal Cheap Ray Bans Wayfarer Sunglasses Outlet Sale lenses may need close to the place, or can be seen touch by hand can feel, but when the user near to far from the conversion, the eye will still be felt large sudden changes.