31/10/2017 0 Comments
Bifocals or Progressive Lenses? Which Is Right for You?
What is presbyopia?
Two of the most important parts of your eye are the cornea and the lens. The cornea is the outer, spherical part of your eye through which light passes. Just below the outer cornea, there is a clear structure called the lens. The lens is expanded and contracted by a muscle that runs along it. As it expands and contracts, light is bent differently, allowing you to focus on objects at different distances.
As we age, unfortunately, the lenses in our eyes tend to harden, becoming less and less flexible. With this decrease in flexibility comes an inability to properly or quickly focus on objects. If you’re over 40 (though there are also conditions that affect younger people that cause a similar hardening of the lens) and are having difficulty seeing, it may very well be presbyopia. Often, however, your vision changes slowly enough that you may not even notice it happening. If you’re holding books further from your face or getting headaches regularly after reading, you should consult your optometrist in Calgary.
How are progressive lenses superior to bifocals?
Invented by one of the founding fathers of the United States of America, Benjamin Franklin, bifocals were made to help people with conditions that affected sight at different ranges. Early bifocals simply combined two different lenses into a single frame, allowing you to see at different lengths in different parts of the frame. This is the reason for the so-called “bi-focal jump” where images will abruptly change as your line of sight passes the border between the different parts of the frame.
Our ability to make lenses has gotten so advanced that stark border of the bifocal is no longer necessary. Progressive lenses are multifocal lenses in the sense that there aren’t simply two or three different distances that are corrected for. Rather, there is a gradient of different ranges that transition seamlessly. These glasses require some getting used to but once you have adjusted to them, they offer all the advantages of bifocals and more.
If it’s the time of year for your eye exam, be sure to ask your optometrist at Crowfoot Vision Centre for more information. Or, if you’ve been wanting new eye glasses, contact us today or stop by our clinic in northwest Calgary.