Conventional prescription eyeglasses are very thick and they cannot be fitted to light weight trendy frames. So the frames were also thick. Totally, a thick eyeglass was worn by people with eyesight problems. They stand aloof from the fashion kings as thin glasses always look trendy. This isolation is now solved with the invention of use of high index plastic material to make lenses for prescription eyeglasses.
The eyesight problem is corrected by eyeglasses by bending the light that is incident on them. For higher prescriptions the light has to be bent more. Thick conventional glasses were used for bending. But the high index plastic material is dense and lesser amount of material is enough for achieving the required bending. Thus eyeglasses made with these lenses are light in weight, extremely flat and ultra thin.
To correct myopia, the conventional glasses were thick at the edges. Thick frames are to be used to match the thickness at the edges. When you look at the eyes of people wearing such types of glasses, the eyes will look small.
To correct hypermetropia, the conventional lenses were thick at the middle. The eyes will look large for us. The glasses will also be heavy and uncomfortable to wear.
Each lens differs with its index of refraction which specifies the amount of light it can bend. This is a ratio of the speed of light in air to the speed of light in the material. Conventional glasses have a refractive index of 1.52 and plastic has 1.50. These material have this index of refraction lying somewhere between 1.53 and 1.71.
As the index number increases, the lenses become denser and thinner leading to a light weight eyeglass. High index plastic lenses are lighter in weight. As the glass becomes more and more thin, it becomes more and more expensive. When very high index plastic is used, the material is very dense and hence increases the weight of the sunglass.
Astigmatism can also be corrected using these lenses. Bifocal and trifocal lenses are also made with the use of these material. These lenses are very thin and perfectly fit in wired frames which are very trendy. Even frameless frames can be used with these lenses. People who wear prescription eyeglasses can also now have the look of an elegant chic with these material.
You have to be careful while buying your high index plastic eyeglass. Thin glasses are now available in optical centers for those with high prescription too. You must consult your optometrist before deciding the index of the lens you need. When you choose the correct one then you will also have the most wanted style and trendy look and I am sure you can make heads turn.Whatsapp us at https://wa.me/918169394813 to know more about High Index Lenses