Are you a first time Bi-focal or Progressive lens user?
Bi-focal or progressive lenses are the type of corrective lenses, which, when a person with presbyopia/reading problem wears, can look at far and near distance without removing their glasses. The only thing to note is that, they have to maintain some head postures and movements while viewing different distances with their Bi-focal/multifocal glasses. It's not that difficult to follow, it just needs three days to a week to get adjusted to. It's just like, when you were learning driving or started using a mobile for the first time. At first you had to know, which gear to put to move forward or backward or which icon/or button to click on your phone to make a call. But once when you were familiar with all of them, it became your second nature. Same is the way with Bifocal/ multifocal glasses.
Bi-focals:
As the name itself says, 'Bi' meaning two and "focals" meaning different viewing distance, collectively 2 different viewing distance.
Top portion of the lenses have distance power or no power (according to your eye prescription) and the bottom portion have near power incorporated in them.
What a user needs to understand is that, naturally when we look at far distances (like looking at the road while driving or looking at T.V or screens in movie theatres or reading billboards), we keep our head and eye gaze straight. And while looking at books or mobiles, we move our gaze downwards, but not the head completely.
(a) Looking at distance with bi-focals on
(b)Reading books/viewing mobile with bi-focals on
Only Head adjustment you have to do is, while looking at the floor or if you are standing on a rooftop and looking at something down, you will have to tilt your head more down, to look from the top portion of the bi-focals. What many people get panicky about is, when they look at floor or stairs through the bottom/reading portion of the lenses.
Progressive(also called multifocals):
They are the advanced version of Bi-focals. In some eye prescriptions, people may be prescribed power separately for intermediate/computer distance that is between 40 to 50cms. They may not be comfortable with the power prescribed for reading, as the reading power will have to be reduced for computer distance. With bifocals, the person will have to adjust the distance between them and computer to see clear. To solve this problem of adjusting distances, progressive lenses are the solution.
Above is a progressive lens design. The top portion of the lens is for the distance, the mid part is for intermediate or computer distance and bottom part is for the reading. It's more or less like bi-focals, the head movement is same even in the case of progressive/multifocals.
In progressive lenses, there are varieties. To know more about them click on the link - Why progressive lenses are expensive? In the article, we have discussed about progressive lens designs, which will help you decide the right kind of progressive lenses to choose. In conventional progressive lens designs, you may have to move or adjust your head more compared to premium progressive lens.
| Bi-focal | Progressive/Multifocal |
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