What's the least lens height can I get?

[fashion glasses]

I need to buy a pair of eyeglasses frame which will give people a sense of dignified and gentle feelings. Always, we care most about fit, comfort and durability when choosing men’s glasses frames, not like the women, and simple design is good for me, ooh, by the way, I need to wear bifocal or multi-focal glasses, so, what's the least lens height can I get?