A thinner lens material, referred to as higher index lenses, can improve the comfort and cosmetic appearance of your lenses by allowing vision correction with a thinner and lighter lens. You may want ...

Well, it made the lenses somewhat radioactive. A post by [lenslegend] explains it all. Exotic elements such as Thorium, Lanthanum and Zirconium are added to glass mixtures to create the high ...

focal length and weighs around 170g (6oz). It has 12 elements in 10 groups, with one aspherical lens, two high-refractive ...