In this particular episode of Ask an Eye Doc, you will learn:
- What a progressive lens is
- The difference between Transitions and progressive lenses
- The difference between bifocals, trifocals and progressive lenses
For you readers out there, here’s the answer in written form:
Let me start out by saying that many people confuse the term “progressive” with “Transitions”. Transitions is a brand of lenses that darken when you step outside into the sun. That’s not what I’m talking about here.
“Isn’t that a bifocal?”, you ask.
Well, no, it’s not. A bifocal is one way to handle presbyopia, but it’s different from a progressive lens. A bifocal has a line. Above the line is your distance prescription, and below the line is your reading prescription. The bifocal only offers you two focusing distances (“bi-“, meaning “two”).
A progressive lens has no line. Instead it progressively adds the bifocal as you get further down the lens (thus progressive). The benefit to a progressive lens is that not only do you get the distance at the top and the reading at the bottom, but you also get all the distances in between (dash on your car, computer, etc).
Some people refer to progressive lenses as “no-line bifocals” or sometimes even “trifocals”. This is not accurate since “bi-” means two and “tri-” means three, indicating they have two and three focusing zones. Because there is a smooth transition from the distance zone to the near zone, a progressive lens actually has an infinite number of focusing distances, so “infinity-focal” might be a more accurate term. But I think sticking to “progressive” is best.
So now you know what a progressive lens is!