Varifocal lenses are the modern day solution for dealing with presbyopia for those of us who wear glasses already. They are normally the ideal solution for those who need one power for ‘distance’, like driving and watching TV, and another strength for ‘near’, such as reading and doing close-up work.
So what is presbyopia? In short, it’s an age-related condition of the eye where it loses a noticeable amount of elasticity and decreases its ability to focus on nearer objects. It is also known as long-sightedness.
The condition can start to manifest itself when we reach our late thirties and into our forties. It’s recognised by us not being able to do close-up work, such as reading and even seeing the computer screen as clearly as we used to do.
There are several ways of correcting the condition. Many people simply use reading glasses. One older solution was to wear bifocal glasses (some still prefer bifocal). However, Varifocal lenses are very much the modern-day solution to correcting presbyopia.
What are Varifocal Lenses?
Varifocal lenses – also known as progressive lenses – offer the user a seamless transition between the distance vision area, towards the top, and the reading vision area at the bottom. There are no sudden jumps or visible lines as you get with bifocal lenses. The lenses simply look like normal ones to the onlooker – which is a massive benefit from an aesthetic point of view.
Are they Easy to Use?
Well, varifocals can take a little getting used to. There’s a technique one has to use so that the correct part of the lens is used effectively for the required viewing distance. Basically, you have to move your head to search and home in on the sharpest point. The distance is at the top of the lens, which is no problem and, similarly, the reading is toward the bottom – again no problem. It’s the arms-length distance where you have to move your head a little to find the sharpest area for your activity.
That’s the vertical vision taken care of! There’s also a technique for finding the horizontal sharp vision point. Again, it involves moving your head a little. The best method to do this is literally to point your nose at what you wish to look at. You will soon find the best focal point for your needs by doing this. After a while, you will be doing this without thinking about it – you’ll find the process of adapting quite automatic.
Are they Suitable for all Glasses Frames?
The majority of glasses frames will accommodate varifocal lenses. Some of the very shallow ones aren’t suitable – you can imagine that the lenses require a reasonable depth in order to cater for all the focal distances (eq, driving at the top through to reading at the bottom). All frames at Spex4less® which are suitable for varifocal lenses will say so in the description. You can also search the Spex4less® website to identify all frames suitable for varifocal glasses. Here’s a direct link to the Spex4less varifocal glasses section.
Are All Varifocal Lenses the Same?
No they are not.
The useable part if the lens is mainly in the central area, stretching from the top towards the bottom. This area is known as the corridor. Either side of this corridor is an area which is of less use and can suffer from some distortion and lack of clarity. It’s an unfortunate feature of all varifocal lenses to some extent. This may be quite dramatic depending upon which lens you decide on. The in-focus part of the lens is the visual corridor – which you have to adapt to – as referred to earlier in this article.
Typically, the differences between progressive lenses are in the width of the useable corridor and the amount of intermediate useable area vertically within this corridor. A deeper lens will be able to accommodate a better intermediate range rather than a shallower lens which will still have a very good distance and reading area, but more limited in the middling focal ranges.
Indeed, depending on which type of varifocal lens you opt for, you will find the visual corridor wider (or shallower) with the levels and amount of distortion towards the horizontal edges, outside of the corridor, varying significantly.
What about Varifocal Lenses Just for Use in the Office?
There is another lens which is now available to those who only require vision correction in the office, or at the computer when at home.
This ‘Office Lens’ is a varifocal lens specifically designed for use up to approximately four metres and is ideal for using a computer or close intermediate work such as plumbing or electrical work. These lenses have a wider reading and intermediate area providing a more comfortable wear. They are available either as being just for computer and reading distances or as computer and reading with a small amount of distance vision at the very top (eg, useful for glancing across the other side of a room).
In Summary!
A varifocal lens will have different strengths on different parts of the lens. At the top, it will have your distance prescription and will gradually change to the correct strength for reading at the bottom. In between, there will be an area that is suitable for intermediate distances such as using your computer or doing ‘arms-length’ work (reading music, using a lectern, making a presentation etc). You will need to move your head, ‘pointing your nose’ at the object you wish to see clearly.
These lenses cover all budgets, and – as with all things in life – the better the lens you require, the higher the cost. However, compared to a few years ago, and as technology has advanced, the prices of varifocal are very reasonable indeed. They now compete very effectively with bifocal lenses and are now seen as the modern day solution for replacing them