Do you already need to use spectacles for activities such as reading? At some point in life, reading newspapers and books becomes difficult for some people. While reading glasses may be an option for some, they may not quite work for you in case you already wear glasses for distance vision. It could be taxing, for example, if you had to swap your glasses all the time. The perfect answer to this common problem is simple and effective-bifocals.
Bifocals were invented by the American statesman Benjamin Franklin. Franklin, apparently had two pairs of glasses, and juggling them all the time was particularly inconvenient for someone as busy as him. He came up with a simple solution that was to change the world of optical accessories forever-he just cut the two lenses in half and fitted them one above the other. He combined his two lenses to make a single bifocal lens that would serve the needs of close- as well as distance-vision. This revolutionary idea has seen many mutations, but has survived as a simple and efficient concept that has been indispensable to the optician.
Bifocal lenses are basically a lens with two different specifications for the top and bottom halves. Some of them have a distinct line separating the two. They are called ‘Franklin lenses’ or ‘Executive lenses’. Nowadays, however, models are available which do show the distinctive line and are called progressive lenses.
The lower part of the lens is for reading purposes, while the upper half is for visibility at a distance. This is because most people look down while reading and up while looking into the distance.
There are basically four distinctive designs for bifocal lenses, four different ways of embedding the reading lens in the other lens. One way is the Franklin lens, as discussed above. Some other glasses have a round part on the lower side of the lens. Others have a slanted ‘D’ shape, or half-moon, while some even go for the ‘ribbon’ segment which is a rectangular position along the lower half of the lens.
All said and done, you may go in for any kind of bifocals you are comfortable with. But all of them work on the same basic principle-the lower part for reading and the upper part for seeing-and the various models only provide minor differences in visual definition and ease. Bifocals may be a bit uncomfortable to start with, but as you get used to them and know how to look through each lens, you will be able to fully appreciate the benefits of the innovation that is the bifocal.
Bifocals are the best way to get rid of two sets of glasses. But it doesn’t mean you have to throw away your old glasses. Just go to an optician with your lenses and tell him to cut them in half so you can make yourself your very own pair of Franklins.