Varifocal Glasses
These work in three ways varifocal glasses, offering good near vision, midrange vision and also distance vision. Varifocal glasses are lenses with no visible line that are used to correct distance vision, at arms length and close-up viewing.
A varifocal lens is a non-fixed focal length lens where the focus changes with focal length. This is in contrast to true zoom lenses, which retain correct focus throughout their focal length range. True zooms have a constant maximum aperture at all focal lengths
