Varifocal glasses, also known as varifocals, varifocal lens, PAL,s or progressive lenses, have a gradual change in strength from the top of the lens to the bottom with multiple focal points in between. This allows you to see all distances and focus points through just one lens.
Varifocals or more correctly "progressives" lenses & are now the preferred multifocal solution.
With the benefits of no visible lines & an intermediate area for use on computers & others middle distance areas this lens is ideal for everyday use for today's middle aged.