If you need glasses for both distance and reading, you may have come across bifocal lenses as an alternative to wearing two separate pairs. But how exactly do bifocal glasses work? Are they still a good choice today, and how do they compare with modern varifocal lenses?
Although varifocals have become increasingly popular, bifocals remain a practical option for many glasses wearers. They provide two distinct prescription powers in one lens, making it possible to switch between distance and near vision without changing glasses.
In this guide, we’ll explain everything you need to know about bifocal lenses, including their advantages, limitations, costs and whether you can have them fitted into your existing frames.
What Are Bifocal Lenses?
Bifocal lenses are prescription lenses containing two different optical powers, typically one for distance vision and another for reading or close-up tasks. Unlike single vision lenses, which contain one prescription across the lens, bifocals incorporate two separate viewing zones.
The upper and larger section is generally used for distance vision, while a smaller segment near the bottom provides additional magnifying power for reading. This lower segment is usually visible as a small D-shaped or rounded area within the lens.
Bifocals are commonly prescribed to people experiencing presbyopia, an age-related change in the eye’s ability to focus on nearby objects. Rather than carrying separate distance and reading glasses, bifocals allow both prescriptions to be incorporated into one pair.
How Do Bifocal Glasses Work?
Bifocal glasses work by dividing the lens into two distinct prescription areas. When you look straight ahead through the upper section, you’re using the distance prescription. When you lower your eyes to read a book or look at your phone, you look through the reading segment. The transition between these zones is immediate, rather than gradual.
This is one of the main differences between bifocal and varifocal lenses. With bifocals, there’s usually a visible line separating the two prescriptions. With varifocals, the prescription changes progressively through the lens without a visible dividing line.
The distance section
The main portion of a conventional bifocal lens is designed to correct distance vision. It’s typically used for everyday activities such as walking outdoors, watching television and looking at objects further away.
The reading section
The lower segment contains an additional prescription power for close-up tasks. This extra power is known as the reading addition, or ADD, and is normally included on prescriptions for people who need additional near-vision correction.
For example, someone might have a distance prescription of +1.00 and a reading addition of +2.00, resulting in a near power of +3.00 in that part of the lens. The reading segment allows them to focus on nearby objects without switching to another pair of glasses.
Who Needs Bifocal Lenses?
Bifocal lenses are most commonly used by people who need different prescriptions for distance and near vision.
This often happens as we get older. From around our early to mid-40s, the natural lens inside the eye gradually becomes less flexible, making it more difficult to focus on close objects. This condition is called presbyopia.
You might notice that you’re holding your phone further away, struggling with small print or needing more light when reading. If you already wear distance glasses, you may find that your existing prescription no longer provides comfortable near vision. Bifocals can be a convenient solution because they combine both corrections. However, they aren’t suitable for everyone. Your optometrist will consider your prescription, visual needs and lifestyle when recommending an appropriate lens design.
What Are the Advantages of Bifocal Lenses?
Despite the popularity of varifocals, bifocals still offer several advantages.
1. Two prescriptions in one pair of glasses
The biggest benefit is convenience. You can see at distance and read close-up without continually swapping between two pairs of glasses.
2. A wide distance viewing area
Most of the lens is dedicated to distance vision, giving you a relatively large viewing area for everyday activities.
3. A clearly defined reading area
The reading segment provides a distinct near-vision zone. Some wearers prefer this to the gradual changes in power found in varifocal lenses.
4. Often more affordable than varifocals
Bifocal lenses are generally less expensive than comparable varifocal lenses because of their simpler optical design. The final price will still depend on the material, coatings and additional lens options.
5. Familiarity
If you’ve worn bifocals successfully for years, there may be little reason to change to another lens design. Many people prefer to keep the type of lenses they’re already comfortable wearing.
What Are the Disadvantages of Bifocal Lenses?
Bifocals also have some limitations worth considering.
The visible dividing line: Traditional bifocal lenses have a noticeable segment line, which some people dislike aesthetically.
Limited intermediate vision: Standard distance-and-near bifocals don’t provide a dedicated intermediate prescription for activities such as desktop computer work.
An abrupt change in prescription: Moving your eyes between the two zones creates a sudden change in optical power rather than the smooth progression of a varifocal.
Adaptation: Some wearers initially notice image jump when their gaze crosses the segment boundary. Stairs and changes in floor level can also require extra care while adjusting.
If you regularly switch between distance, computer screens and reading, varifocal or occupational lenses may be more suitable.
Bifocal vs Varifocal Lenses: What’s the Difference?
Both bifocals and varifocals can correct distance and near vision, but they work differently.
| Feature | Bifocal Lenses | Varifocal Lenses |
|---|---|---|
| Prescription zones | Two distinct powers | Gradual progression through multiple powers |
| Visible dividing line | Usually yes | No |
| Distance vision | Yes | Yes |
| Intermediate vision | No dedicated zone in standard distance/near designs | Yes |
| Reading vision | Yes | Yes |
| Adaptation | May require adjustment | May require adjustment |
| Typical cost | Generally lower | Generally higher |
Varifocal lenses provide a gradual transition between distance, intermediate and near vision, making them especially useful for people who need clear vision at several distances throughout the day.
Bifocals, on the other hand, may suit people who primarily need distance and reading correction and prefer clearly separated viewing areas.
The best choice depends on your prescription, daily activities and personal preferences.
Bifocal vs Single Vision Lenses
The main difference is straightforward.
Single vision lenses contain one prescription across the lens and are normally designed for one viewing range.
Bifocal lenses contain two different prescription powers within the same lens.
If you only need glasses for distance or reading, single vision lenses may be sufficient.
If you require correction for both, bifocals offer a way to combine those prescriptions without carrying separate pairs.
For a more detailed explanation, read our guide: What Are Single Vision Lenses? A Complete UK Guide.
Can You Get Bifocal Lenses Without a Visible Line?
Traditional bifocal lenses usually have a visible segment line separating the two prescription areas. If you prefer a lens without a visible dividing line, varifocal lenses are generally the more common alternative.
Varifocals incorporate different prescription powers through a smooth progression, without the distinct segment found in conventional bifocals. However, it’s important to understand that varifocals have different optical characteristics and may require a period of adaptation. An optometrist can help determine whether switching lens designs would suit your needs.
Are Bifocal Lenses Good for Computer Work?
Not always.
Traditional bifocal lenses are normally designed for distance and close-up reading, with no dedicated intermediate zone.
A desktop computer monitor is usually positioned further away than a book but closer than objects viewed at distance. This can make computer work awkward through standard bifocals. Some wearers find themselves tilting their heads or adjusting their posture to see the screen clearly.
If you spend several hours a day working at a computer, you may benefit from single vision intermediate lenses or occupational lenses designed for office environments. These can provide more comfortable viewing at typical desk and screen distances.
Can Bifocal Lenses Be Transitions®?
Yes. Depending on the lens specification and availability, bifocal lenses can be made with photochromic technology such as Transitions®. Photochromic lenses darken in response to certain light conditions and return towards a clearer state when those conditions change.
This means you can have distance and reading correction in one pair of glasses, with lenses that also adapt to changing light outdoors. Different photochromic products offer different tint options and performance characteristics, so availability should be checked for your particular bifocal design and prescription.
Can Bifocal Lenses Be Used in Sunglasses?
Absolutely.
Bifocal prescription sunglasses combine distance and reading correction with tinted lenses. They can be useful for activities such as reading outdoors, relaxing on holiday or checking your phone in bright conditions.
Depending on your prescription and frame, different tint colours and lens options may be available.
And if you already own a favourite pair of sunglasses, you may be able to have them reglazed with new bifocal prescription lenses rather than buying a completely new pair.
Can You Put Bifocal Lenses Into Existing Frames?
Yes — and this is where The Glasses Guys can help.
If you already have frames that you love, you don’t necessarily need to replace them when your prescription changes or you decide to move to bifocal lenses. Through a process called reglazing, your existing lenses are removed and replaced with new prescription lenses made to fit your frames.
This means you can keep your favourite glasses while upgrading the lenses to suit your current prescription. At The Glasses Guys, we offer prescription lens replacement for suitable existing frames, including bifocal, single vision and varifocal options.
Frame condition, shape, size and suitability for the required lens measurements all need to be considered before reglazing.
How Much Do Bifocal Lenses Cost in the UK?
The price of bifocal lenses varies depending on the prescription, lens material, coatings and any additional features.
Standard bifocal lenses are generally more affordable than comparable varifocal lenses, although thinner materials, photochromic technology and specialist finishes can increase the price.
If your existing frames are still in good condition, reglazing can be a cost-effective alternative to buying a completely new pair of prescription glasses. Rather than paying for new frames as well as lenses, you can focus on replacing the lenses you actually need.
Are Bifocal Lenses Still Worth It?
Yes. Although varifocals are popular, bifocals remain a practical option for people who need clear distance and near vision.
They’re particularly worth considering if you prefer a clearly defined reading segment, don’t require a dedicated intermediate viewing zone or have already worn bifocals comfortably for years.
However, if you regularly use a computer or need to see clearly across several viewing distances, varifocals or occupational lenses may offer greater flexibility.
Ultimately, the right choice is the one that best suits your prescription and everyday visual needs.
Keep Your Favourite Frames With New Bifocal Lenses
Changing your prescription doesn’t have to mean changing your glasses.
At The Glasses Guys, we specialise in fitting new prescription lenses into customers’ existing frames.
Whether your current bifocals are scratched, your prescription has changed or you’re considering bifocal lenses for the first time, reglazing allows you to keep the frames you already enjoy wearing.
Keep your frames. Replace your lenses.
Explore our bifocal reglazing options and give your favourite glasses a new lease of life.
❓ Frequently Asked Questions
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Bifocal lenses are used to correct two different viewing ranges, most commonly distance and near vision. They allow wearers to see distant objects and read close-up without changing glasses.
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Bifocal lenses have two distinct prescription zones, usually separated by a visible line. Varifocal lenses provide a gradual progression between distance, intermediate and near vision without a visible dividing line.
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Yes, provided your vision meets the relevant legal driving standard and your glasses are suitable for driving. The distance portion is generally used for looking at the road, while the near segment may help with closer tasks. Ask your optometrist if you’re unsure.
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Neither is automatically better. Bifocals may suit people who primarily need distance and reading correction, while varifocals offer additional intermediate vision and a line-free appearance.
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Yes, if your existing frames are suitable for reglazing. New bifocal prescription lenses can be manufactured and professionally fitted into your frames.
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Traditional bifocals usually have a visible line separating the distance and reading sections. Varifocals are a popular alternative for people who prefer lenses without this line.
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Standard distance-and-reading bifocals may not be ideal for computer work because they lack a dedicated intermediate zone. Intermediate or occupational lenses may provide a more comfortable option.
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Yes. Depending on your prescription and lens design, thinner lens materials may be available. Your frame choice and prescription will influence the most suitable option.
