What Are Bifocals and How Do They Work?

OK...you'r over 40 years old and you can't read things up close. Maybe you have to take your glasses off and you can read. Maybe you need those $3.00 cheapo glasses from the pharmacy, even putting them on over your contact lenses. But you're starting to get cranky because of all the on-and-off with the glasses stuff. What to do? It's time to talk about bifocals.

Bifocals are glasses that have both a correction for your distance vision on the top of the lens, and a correction to help you read on the bottom. The first bifocal was actually invented by Benjamin Franklin. Yup...the same guy who did the whole kite and key thing to discover electricity! Ol' Ben just glued the top half of one lens to the bottom half of another and created what we now call an "Executive" bifocal.





This very simple type of lens has evolved into into more modern bifocal lenses. The most direct descendant of the Franklin lens is the Flat-top bifocal. These lenses have a very large area devoted to your distance vision, with a smallish insert or segment that allows you to focus on objects up close. The working distance, how far away you can hold something and still be in focus, is fixed with this type of bifocal.

What about seeing things a little further away, say a computer screen? And by the way, I think those bifocals where I can see the lines make me look older. Isn't there some kind of newer lens?




Absolutely! The most modern bifocal lenses are called "No-line" or "Progressive" lenses. These lenses have a smooth change in focus from the topo of the lens (distance), through the middle (arm's length), to the bottom of the lens (reading distance). We say that there's a "column of clarity", a sweet spot for each working distance for our vision. This column is usually shaped somewhat like an hourglass.

Our favorite Progressive lenses at Skyvision are Varilux products like the Varilux Comfort or the Varilux Physio. We always try to match the strengths of a particular lens to your special visual needs. Our doctors and opticians are experts on making this match. If you are having trouble with reading come on in and learn all about bifocals!

Hey! My Arms Shrunk!

We know what you're thinking...who shrunk my arms? It's happening a lot around the office at Skyvision Centers, too. We're all getting a little older  around here and it seems like there are a bunch of reading glasses lying around everywhere now. As a matter of fact, the only person in the office who can't seem to find Dr. White's readers is DR. WHITE!

Why do we start to have trouble reading when we get older? To answer that we have to go all the way back to age 2 or so. Almost all of us is born a little farsighted or hyperopic. We focus our eyes to overcome this little bit of farsightedness using the same muscles that we use to focus on objects up close. This muscular process is called ACCOMMODATION. When we look at things up close three things happen: our eyes come closer together, our pupils get smaller, and the lens inside our eyes gets fatter. We have massive powers of accommodation at age two and then we gradually lose those powers as wel get older.

The medical term for "Over 40 Eyes" is PRESBYOPIA. When we lose enough of our power of accommodation that we can no longer see things up close we become presbyopic. Of course your kids will just say you got old! Here's a LINK to the Eyemaginations video on presbyopia.

So what can we do? Well, there are a bunch of options, actually. If your eyes are health you can just buy reading glasses at the pharmacy. You might have a different prescription in each of your eyes, and if so your Skyvision Centers eye doctor can prescribe a pair of reading glasses that are specific to you. Many of us need to wear glasses to see things far away--a pair of bifocals takes care of the up-close problem. Bifocal contact lenses are available, and you can even correct your vision with something called MONOVISION, with one eye corrected for near and one eye corrected for far vision.

Whew! That's a lot of options! Don't worry...we'll have lots of answers for you in future posts, and of course,  you can go to the SkyVisionCenters101 YouTube channel see several "Dr. Whiteboard" videos about bifocals!

Bifocals: How Do They Work?

Bifocals   . . . .

Yes, many people wear bifocals yet, even more want to know what exactly a bifocal lens is and how does it work?   There are bifocal lenses with a line, there are bifocal lenses with no line, called progressive lenses.   Watch this video by Dr. Darrell White at the SkyVision Centers Dr. Whiteboard for the answers!


Dr. Whiteboard Video onYouTube - Bifocals

Debunking Eye Myths*

How many times have you heard someone tell you something about your eyes or your vision that made you scratch your head? Something that you've heard a thousand times and always wondered about? Us too!

Let's look at a couple and see how they stack up to reality:

1) "Don't sit so close to the TV; you'll ruin your eyes!"

FALSE! It turns out that this one was never true. There has never really been anything harmful coming out of a TV screen, at least as far as your eyes go. People have been sitting closer to the TV for decades just to see better. Kids have a natural tendency to do this. It doesn't necessarily mean that you need glasses, and sitting closer definitely won't hurt your eyes or your eyesight. Cable TV might rot your brain...

2) "Don't read in the dark; it'll make your eyes weak!"

FALSE! Reading in dark or dim light just makes reading harder, but it doesn't do any harm to your eyes or your vision. Heck, Abe Lincoln used to read by candlelight as a kid, and HE turned out alright!

3) "If you wear your reading glasses you'll just need to wear them more."

TRUE and FALSE. Once you hit your 40's almost everyone starts to lose the ability to focus up close due to a combination of hardening of the lens in your eye and decreased strength in your focusing muscles. You will need more help with reading glasses or bifocals in time no matter what, but fighting against them by forcing yourself to focus can make you need them a little less for a little longer. Use 'em or don't, whichever makes you more comfortable.

4) "Give your eyes a break, you're gonna wear them out!"

FALSE. Your eyes are different from a muscle like your biceps. You can't wear them out. Go ahead and use them!

5) "If you don't stop it, you'll go blind".

WHOA! Wait a minute. This is a PG-rated blog! :-)

*Props to Dr. Carey Silverman for the idea.