Some of the commonest questions that we get are about varifocals, so I was wanting to go through a little bit about varifocals, about what they are, how they work, things like that. Quite often, people, they've heard of them but they don't really know what they do and don't really understand how they work.
Now, I'm actually wearing varifocals right now and, if you watch the above video, you can see, there's no little line. The old fashioned bifocal is the one with a line. The difference there is, you've got two areas of vision in the bifocal. You've got your distance vision, and then you've got your line and your little segment which has the close vision, and you've got that missing bit in the middle which is around your arm’s length.
The difference with a varifocal is that it gradually changes the power from the top of the lens at the pupils, all the way down to the very bottom of the lens, which has got the strongest reading power. You've got the power there for every distance away from you. You've got your close reading and you've got your middle distances for computers and laptops, all the way out to the far distance.
So that sounds great, but there are a few issues with varifocals! The way it works, as the power changes down the lens, we've got to change that curve in the lens to create a different power. The powers of all spectacle lenses are down to the material that's used to make the lens based on how much it bends the light and the curves on that lens. So the curve down the lens has to change to create a different power, which sounds great. But, actually, physics doesn't like that. Physics says, "No, definitely not." That will actually just create a massive blur, a big distortion. All varifocals have the distortion pushed out to the sides. That's the design of the lens. We make a big deal about the lens design. What have they done to that lens to improve the areas of clear vision and reduce the distorted areas? That's what we talk about when we talk about lens design and that is the critical thing about varifocals, the design of the lens.
Some people who already wear varifocals will probably know there's not just a varifocal. If there was one perfect varifocal, that would be wonderful. All opticians could offer you the same great varifocal but there is not. There are hundreds of varifocals available on the market, probably thousands actually, because as technology changes, the lenses improve. A more basic varifocal will have more distortion and a narrower corridor of clear vision down the middle.
Next a mid range design of varifocal will have wider areas of clear vision down the middle and less distortion at the sides. And then you've got more of a top of the range, more technologically new design, where you've got even less areas of distortion and even wider areas of clear vision. Not all varifocals are equal, unfortunately, and not all varifocals between each optician are the same. When you're talking about varifocals, you want to know the design. What have they done to minimize the distortions in that? How good is that design? When was it released? Is it a new design? Are we looking at a design that's 10 or 20 years old? Are we looking at something that's a year or two old?
That gives you a little bit of insight into varifocals. As I mentioned, I'm wearing varifocals. I wear them all day, every day. I absolutely love them. I think they're fantastic. Some people will have have problems with varifocals - It's how your brain deals with those different areas and those distorted areas which is why you must talk to your Optician and get good advice before buying varifocals. But to give yourself the best opportunity to get on with a varifocal, you want to be choosing the best design, i.e., the one that minimizes the distortion and the one that gives you the widest and clearest areas of vision.