Multi-Focal Lenses
What are Multi-Focal Lenses?
As their name suggests, multifocal lenses enable you to have more than one prescription built into the lens so that you only need one pair of glasses, for multiple uses.
There are two main types of multi-focal lenses: Bifocals and Varifocals.
Bifocals:
What are Bifocals?
Bifocals are multifocal lenses which have two separate optical powers. They are divided into two parts to accommodate a combination of any two different prescriptions into one lens. One area of the lens will have one prescription (usually distance) and a segment in the lower half will have the other (usually near vision).
How do bifocals work?
Rather than having two pairs of single-vision glasses, bifocal lenses can be a more convenient solution as they combine all your vision needs into one pair of glasses.
Bifocal lenses are typically worn by people over the age of 40-45 who need additional help with their near vision due to the effects of presbyopia where the crystalline lens inside the eye naturally begins to lose its ability to focus on near objects.
How to tell if you need bifocals?
As we get older, we’ll start to find it more and more difficult to read or focus on things that are close up. This is called presbyopia and is a perfectly normal part of ageing. Most people become aware of presbyopia when they start holding their phone or books further away in order to see it clearly.
Presbyopia will start to happen around the age of 40. If this sounds familiar, and you already wear glasses, it might be time for an eye test and to maybe give bifocal reading glasses a go.
Varifocals:
Varifocal lenses allow you to see at any distance, because they have different sections for viewing close up and far away and everything in between. So whether you’re driving, using a computer, shopping or reading, you can wear one pair of varifocals to accommodate all your vision needs.
Modern varifocals can be described as having three ‘portions’ of vision within a single lens:
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Long distance at the top
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Reading at the bottom
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Intermediate in the middle
As a result, they have an element of peripheral distortion, which is completely normal due to their design. Higher-quality varifocals manage the distortion better by moving it towards the edge of the lens and providing a greater field of vision and ease of use for wearers. We offer various types of varifocals in practice so please do not hesitate to ask us about them.
Basic varifocal designs are often described as ‘one size fits all’ as they are made under the assumption that a prescription is only spherical. This means that it can be difficult for people with stronger prescriptions to adapt to basic varifocals, especially those with high astigmatism.
How do varifocals work?
Varifocal lenses work by changing power from the top to the bottom of the lens. Moving your eyes up and down the lens will give you clear vision at all the distances you need.
How long does it take to adjust to Varifocals?
Getting used to varifocals can take from as little as a few days to a few weeks. You need to give your brain sufficient time to adjust to the new prescription and viewing areas, which can take a bit longer if you are trying varifocals for the first time.
It might feel strange at first but the best way to adapt is to keep wearing your varifocal glasses so that your eyes can gradually adjust. Thanks to the detailed measurements we take, most people adjust quickly but others may experience slight dizziness at first when moving quickly from one viewing area to the next. Don’t worry these sensations don’t last long and we’re always available to reassure you if you are struggling.
