Glasses Lenses - Eyeglasses Lenses

Sometimes, when you order your prescription glasses at local stores, the optician may asked you if you need to add special prism in the new eyeglasses lenses, so, what do you know about the prism? It takes me much time to understand it correctly. They are suggested to utilize in crossed eyes, lazy eye, or some other eye diseases!

Actually, the first time I heard about prism was about 10 years ago in physics, I was a high school boys that time. We know that the thickness of a lens is different from the center to edge, while the thickness affects the light bending property of eyeglasses lenses. When the light is coming through, thicker area slows down the speed and thinner one is on a opposite side. While a prism’s slowing ability is between the bottom and apex of a lens, and then the direction of the light can be changed, and how much it changes is determined by ratio of the index of material refraction to the air. So, the optometrists today can provide denser materials for prescription eyeglasses lenses!

Some people may have a eye problem of double vision, it dues to one’s eyes can turn up or down, in or out as well, part of them are inborn, others are a posteriori, people always needn’t to worry much about the former kind as the brain has the capacity to suppress or turn off the area of vision that results in the eyes perceiving double at early ages. However, you eye doctor may suggest you to take a surgery or add a prism in your eyeglasses lenses if this vision problem is formed lately in your life. Some people may have the idea that if the prism looks like a strange looking triangle in glass lens, actually, it isn’t, as it usually can show up the thin and thick area on the eyeglasses lenses. And what’s more, there can be some fluctuation when you lenses are first time added with such prism, the eyeglasses prescriptions may change frequent, that’s reason why you need some time to adjust this situation. Actually, not only because of this reason that you need a prism, if you have to work at computers long hours every day, eyestrain and fatigue are usually a common problem when reading, and prisms may be used to solve this problem effectively!

Additional, add a prism in your eyeglasses lenses may be expensive for someone, but not too much, you can try online sites, which can provide you just for several dollars!