Trifocal Lenses provide visual corrections for 3 fields of vision, which are Distance (always on the top portion of the lens) Intermediate (always in the middle) and Near (aka reading, which is always on the bottom portion of the lens).
Trifocal lenses are also known as Straight or Flat Tops segments. The Trifocal lenses will have 2 horizontal segment lines that run partially through the lenses. We offer 2 sizes of bifocals, the FT-7x28mm segment and the FT-8x35mm segment. Please be aware that the Trifocal visual fields and segment sizes are NOT customizable. The Intermediate zone width of the trifocal lens is dependent on which size you order for the FT-7x28mm it is 7mm wide and for the FT-8x35mm the segment width is 8mm wide.