A convincing testimony to the technological improvements in the eyewear industry is that progressive eye glasses succeeded well the traditional bifocal reading glasses and trifocal glasses. As a latecomer, progressive glasses are supposed to offer more benefits associated with visual correction. This is absolutely true. The inventors of progressive eyeglass lenses did this work just with clear mind of making progression. Compared with conventional bifocal reading glasses or trifocal eyeglasses, progressive spectacles do have some advantages which are brought by the unique and complicated lens design. The most noticeable breakthrough made by progressive lenses is that a gradient of increasing prescription lowers could be incorporated into a single lens.
Such a powerful lens is incomparable. This is because a bifocal lens has a universal design with only two powers and a trifocal lens only adds an additional power. Thus, the functionality of vision correction enabled by progressive eye glasses is also superior to that of either bifocal glasses or trifocals. It is true that people can get visual aids at near, intermediate and distance ranges from a pair of trifocal spectacles. And the extra visual help at the intermediate zone marks the difference between bifocals and trifocals. However, objects within all distances can be controlled by a pair of progressive spectacles. Compared with bifocals and trifocals, progressive reading glasses come with a smoother power transition.
Another advantage of progressive eye glasses is old-age-related. Both bifocal and trifocal reading glasses are obviously associated with “old age” because they have visible segments or lines on the lens surface. Progressive lenses have never these “age-telling” lines or segments. For a certain group of people especially female ones, it is unpleasant to let others know their age. In this case, progressive eyeglasses are more cosmetically attractive. Most wearers can adjust to the additional lens power by tilting the head to sight through the appropriate part of the vertical progression.
C: Progressive eye glasses as a later comer have some valuable advantages over traditional bifocal reading glasses and trifocals. They provide a smoother power transition and more cosmetically attractive look.