These latest-generation lenses are called trifocals because they offer clear vision at middle distances, which is generally anything at arm’s length. This is in addition to providing near and far vision.
What’s more, trifocal lenses allow a person to switch effortlessly between all three distances – near (reading) distance, long distance and the in-between distances. Vision is clear at all those points – something the previous multifocal IOLs couldn’t achieve.