progressive glasses

My step mother has just arrived and she brought with her a newly purchased progressive glasses for my father. My father has told me already about progressive lenses a few months ago. He explained to me that it’s an eyeglass which is sometimes called “no-line-bifocals” because the visible lines of traditional bifocals and trifocals are being eliminated. Indeed, when my father wore his new progressive glasses, you will never know that he is wearing reading glasses.