Varifocal glasses also called progressive eyeglasses, which are used to correct presbyopia and other disorders of accommodation. Varifocal glasses are lenses with no visible line that are used to correct distance vision, at arm's length and close-up viewing. To make sure your lenses work as well as possible, you need a frame that will optimize the way they work. This means making sure the lens height no less than 28mm to fit in the different prescription.
Moreover, because varifocal glasses have different prescriptions in different places, you will need to use them differently depending on what you are doing. The top part of the lens has your distance prescription and you will use this for looking at things that are further away, when doing things like watching television, going to theatre or admiring a view, for example. The progressive corridor or the place where the lens changes between your distance and reading prescriptions, is in the middle of your glasses. You will use this part of the lens for viewing things at mid-range, such as when using the computer or cooking. The lower part of the lens is where the reading prescription will be, and you will use this to do any close work, things like reading, sewing, or anything intricate like painting.
They have three invisible zones that allow easy viewing transition between zones - allowing sharp vision from near to far in one lens. Progressive lenses are designed using state-of-the-art optical technology, and when adjusted to the individual's specific needs, they provide great wearer satisfaction. Sometimes, however, a little training is necessary for people to get used to wearing progressive lenses. The eye and the brain have to learn to adjust to the different refractive powers of the lenses. Here is an example: When someone wearing progressive lenses climbs stairs, they will look through the lower portion of their lenses. In progressive lenses, this is the area that is adjusted for a reading distance of approximately 40 centimeters. The stairs are, of course, depending on their size, clearly further away. Thus the stairs will be viewed with distortion. The good news: The sense of sight is highly complex - and it is also a very adaptable system. Within a short period of time, it is able to learn and to adapt to new viewing conditions; so when climbing the stairs, a wearer simply points his head somewhat further downwards.