What HI Index lenses are?
Type of lens with a higher index of refraction, meaning that light travels faster through the lens to reach the eye than with traditional glass or plastic. It is denser, so the same amount of visual correction occurs with less material (whether glass or plastic) — so the lens can be thinner. If you hate thick prescription eyeglasses, try lenses in a high-index material. They offer superior optics in a thinner, lighter lens.
