Here are popular eyeglass lens materials, arranged in order of refractive index and lens thickness (pretty good indicators of cost). Except for the crown glass, these are all plastic materials.
Key Features and Benefits
1.70 to 1.74
36 (1.70) 33 (1.74)
The thinnest lenses available. Block 100 percent UV. Lightweight.
1.60 to 1.67
36 (1.60) 32 (1.67)
Thin and lightweight. Block 100 percent UV. Less costly than 1.70-1.74 high-index lenses.
Thin and lightweight. Significantly more impact-resistant than CR-39 plastic and high-index plastic lenses (except polycarbonate and Trivex). Higher Abbe value than polycarbonate. Downside: Not yet available in a wide variety of lens designs.
Superior impact resistance. Blocks 100 percent UV. Lighter than high-index plastic lenses.
Superior impact resistance. Blocks 100 percent UV. Higher Abbe value than polycarbonate. Lightest lens material available.