Hi-Index lenses (Thin lenses) :

As consumers, our interest in thin and light extends to more than just potato chips and beer – it has impacted eyeglasses in a very significant way. Most eyeglass wearers are nearsighted, and a basic physical property of nearsighted lenses is that their edges are thicker than their centers. The stronger the prescription, the thicker the edges (see lens drawings below). Most of today’s fashionable frames are made of plastic or metal with rims thinner than the lens itself. Aso very popular are rimless mountings, where the lens edges are completely exposed. in either case, the lens edges are highly visible, and thicker edges can detract from the appearance of the eyewear. We provide four kind of thinner lenses: 1.57 called thin and lite, 1.6 called super thin, 1.67 called extra thin and 1.74 the thinnest lenses in the world.