TRIVEX 1.53 lens material index is up to 30% thinner than the the standard 1.50 material. The most lightweight material available gram for gram with only a 1.1 specific gravity. 9 times more resistant to breakage compared to 1.50 index lenses. The ideal choice for rimless and drill design frames. Improved scratch resistanceto that of Polycarbonate. Abbe value of 45 allows exceptional image quality.