Special Lens Design Of Bifocal Reading Glasses Progressive
People with much knowledge of reading glasses and its variations may have heard of the basic point that bifocal reading glasses progressive is superior to those traditional bifocal reading spectacles or trifocal ones. After more than two hundred years progression, bifocal reading glasses as well as other variations have formed an integrated group for presbyopia correction. It is true that eyeglasses equipped with progressive lenses are usually called progressive eyeglasses. But another name is no line bifocal reading glasses. Another similar type of eyeglasses is called trifocal reading glasses. There have been claimed a lot of differences among these three types of reading spectacles. However, it is feasible to differentiate one from another in accordance to their functionalities, which originate from varying lens designs. This article pays exclusive attention to these different lens designs.
bifocal reading glasses progressive differs considerably in lens design from trifocals and bifocals. In fact, these differences can be reflected by their respective names. In brief, a bifocal lens has two separate lens powers. A trifocal lens has three different lens powers. And a progressive lens has a couple of varying lens powers. In some cases, lens power is also called focal point. In this case, a progressive lens is made with a few local points. This is the most obvious difference of focal point suggested by their specific names.
Moreover, bifocal reading glasses progressive differs from the other two types of reading glasses in power arrangement as well. It is widely known that the two powers of a regular bifocal lens are separated by a visible line on the lens. Similarly, two lines set in a trifocal lens separate obviously its three powers. However, a progressive lens do not has such kind of power separation. As the name indicates, a progressive lens offers a progressive power transition from the top to the bottom part of the lens
