Which Prescription Lenses Should I Choose?
This is a very important question. We will help you understand and determine which is the best lens to choose to choose for your prescription and why.
Firstly, you need to determine what you want the glasses for.
Will they just be single vision lenses, or do you need a bifocal or a varifocal?
When you go to the opticians to have a sight test, all the different lens options my not be fully explained to you.
You don’t get to decide what type of prescription you need. That’s a decision in most cases the optician has already made, based on your eye exam results, and they will recommend the best choice of lens for you.
This is standard practice and, although you might not “choose” the type of lenses that you need, you will surely want to know what you will be paying for and why you have been given this recommendation.
Single Vision Lenses
Single vision lenses as the name implies, correct one single aspect of vision, be it distance, intermediate or near.
These glasses will be most people’s choice until biological changes in the eye start to happen, around the age of 40 or so.
They are the simplest type of lenses, also they are the least expensive. Our standard CR39 lenses are free across the range.
Single vision lenses offer the largest field of view of any lens type.
They correct longsighted, shortsighted and astigmatic prescriptions.
Before the advent of varifocal lenses, bifocal lenses were the only choice for anyone who wanted to see in the distance, and read at the same time with one pair of glasses. They still offer excellent visual outcomes at both distances.
There is the standard bifocal, which is a distance lens which incorporates a section in the shape of a D on its side for the near vision .
You can also have a lens where the dividing line goes all the way across, so the lens is split, this is called an executive bifocal.
At GTTM we offer a new type of bifocal, which has all these excellent optical properties, but does not have the visible dividing line so that aesthetically it looks like a normal single vision lens.
Varifocals are the eyeglass industry’s version of a perfect lens. The aim is to give great vision at all distances, to people who are over the age of 38, and want one pair of glasses, which will deliver optimum clarity for all visual distances.
They achieve this by having the distance power in the top of the lens, and gradually increasing the power in a corridor, moving down the lens.
So, rather than having a specific strenght across the entirety of the lens, as in single vision, the eye will visually select ‘zones’, with a focal spectrum.
This is how varifocal lenses offer multiple visual corrections in one lens. This allows you to focus on distance, intermediate and near.
The compromise with a varifocal, is that the vision can feel a little bit strange if you look out of the side of the lens, this is called the ‘swim’ effect.
At GTTM we only use the latest freeform varifocals, this practically eliminates any ‘swim’ effect.
Our premium varifocal would cost over £250 on the high street, we can offer a massive discount on this.
These are lenses which darken when you go outside.
They offer an all in one solution, giving you the best of both worlds, saving the need to carry an extra pair of prescription glasses.
This obviously gives you much less chance to misplace any spare sunglasses.
They also filter out 100% of all harmful UV rays emitted from the sun. This leads to healthier, happier eyes, with less long term issues futher down the line, like cataract or macular degeneration (ARMD).
They are also very good at filtering out any glare especially when the sun is out.
Less glare = Less eyestrain.
They also offer blue light protection.They will block out some of the harmful blue light which we come into contact with when we are outside, and also increasingly when inside, due to devices like tablets and mobile phones.
There are also some limitations to transition lenses which you need to be aware of.
They will darken when you go outside, not only in the sun, but also when it is overcast, or raining. This is because they are triggered by UV rays from the sun, which are always present.
They will not work very well in the car.
Again this is because UV will not penetrate the car windscreen.