Anything above a 6
should use a 1.74; the thinnest lens around.
Bifocal is a two-part lens. Distance and reading in one.
Progressive is a no-line bifocal.
Scratch resistance: an extra layer of scratch-proofing.
UV Coating: Protection against the sun.
Anti-reflective coating: Mainly used to block glare from computers or lights. Makes vision sharper, and the lens clearer.
Crizal: an anti-reflective, anti-fog, and anti-smudge coating.