1.56 photochromic round-top bifocal, 1.56 photochromic flat-top bifocal, 1.56 photochromic semi-finishes single vision, 1.56 photochromic semi-finished round-top bifocal, 1.56 photochromic semi-finished invisible bifocal, 1.56 photochromic semi-finished flat-top bifocal, 1.56 photochromic semi-finished progressive