Varifocal glasses are also called "progressive glasses", they have different vision sections. They are typically designed for people over 40 who have difficulty focusing on close-up objects.
Varifocal lenses work by changing power from the top to the bottom of the lens. Moving your eyes up and down the lens will give you clear vision at all the distances you need. This means if do some sewing, you would be able to thread a needle easily.