Varifocals vs Bifocals: Key Differences and Which to Choose

Bifocals and varifocals both correct vision at more than one distance in a single pair of glasses, but they do so in different ways. Bifocal lenses have two distinct viewing zones separated by a visible line. The upper portion is for distance and the lower portion is for near vision. 

Varifocal lenses have no visible line and instead offer a gradual transition from distance vision at the top, through an intermediate zone in the middle, down to near vision at the bottom. 

The key practical difference is that varifocals provide clear sight at three distances, while bifocals cover two. Varifocals look more modern and cosmetically discreet, but they typically cost more and may require a short adaptation period. 

At a glance:

• Bifocals have two vision zones and varifocals have three.
• Bifocals have a visible line on the lens, varifocals don’t.
• Bifocals are generally more affordable and quicker to adapt to.
• Varifocals offer a smoother, more natural transition between distances.
• Both lens types correct presbyopia and reduce the need for multiple pairs of glasses.

What Are Bifocal Lenses?

Bifocal lenses contain two separate prescription zones within each lens. The larger upper section corrects distance vision, while a smaller segment at the bottom provides magnification for close-up tasks such as reading. These two zones are divided by a visible horizontal line, sometimes called a "segment line" or "D-segment." 

Bifocals are most commonly prescribed to people with presbyopia, a natural age-related condition in which the eye's lens becomes less flexible, making it harder to focus on nearby objects. If you find yourself holding a book at arm's length or squinting at your phone, presbyopia is the likely cause.

How Bifocals Work

When wearing bifocals, you look through the upper portion of the lens for distance tasks (watching television, walking, recognising faces) and tilt your gaze downward through the lower segment for near tasks (reading, checking your phone, handwriting). 

The transition between the two zones is immediate, which some wearers find helpful because each zone is clearly defined. 

With no intermediate prescription zone, it means activities at arm's length, such as viewing a computer screen fall between the two focal points and may not be as sharp.

Pros and Cons of Bifocals

The primary benefit of bifocal lenses is their affordable convenience. They allow individuals with both distance and near vision problems to correct both issues in a single pair of glasses. This eliminates the need to constantly switch between two pairs of glasses, which can be inconvenient as well as time-consuming and costly. Additionally, bifocals can help prevent eye strain and headaches caused by trying to focus on close-up objects with distance lenses.

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What Are Varifocal Lenses?

Varifocal lenses, also known as progressive lenses, graduated lenses, or multifocal lenses, correct vision at three distances within a single lens, with no visible dividing line.

The prescription power changes gradually from the top of the lens (distance) through the middle (intermediate) to the bottom (near). 

This design means you can see clearly whether you are looking across a room, working at a computer, or reading a book, all without swapping glasses. Additionally, no distinct eye movements are necessary to switch between the desired vision correction, making them a more natural option than bifocal lenses.

How Varifocals Work

The lens surface is engineered with a smooth "corridor" of changing prescription power that runs vertically through the centre. To use each zone, you adjust your head position slightly, looking straight ahead for distance, lowering your gaze slightly for a computer screen, and dropping your eyes further for reading. 

The progressive design does introduce narrow areas of mild distortion at the left and right edges of the lens, particularly in the intermediate zone. This is a normal characteristic of all varifocal lenses, though higher-quality designs minimise it significantly.

We offer a wide selection of varifocal glasses to meet your prescription needs. Perfect for the upcoming summer months to protect your eyes from harmful UV rays.

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Conclusion: A Practical Guide to Choosing Varifocal or Bifocal Lenses

Both varifocal and bifocal lenses offer correction for multiple vision problems in one pair of glasses. The best lens for you depends on your daily activities, visual demands, and personal preferences. Below is a practical breakdown by common use case.

Best for Reading and Close-Up Work

If your main concern is switching between distance vision and reading, bifocals may be all you need. 

The clearly defined near zone provides strong magnification for close-up detail, and the straightforward design keeps things simple.

Varifocals will give you a more complete solution If you also spend time on tasks at arm's length, because they include the intermediate zone that bifocals lack.

Best for Computer and Desk Work

Varifocals are generally the better choice for anyone who spends significant time at a computer or laptop. The intermediate zone in a varifocal lens is designed for exactly this distance, meaning you can see your screen clearly without tilting your head into an awkward position. 

Bifocals do not include an intermediate zone, so computer screens often fall in a "no man's land. Some bifocal wearers compensate by raising or lowering their monitor, but this can lead to neck and shoulder strain over time.

Best for Driving and Outdoor Activities

Both lens types provide clear distance vision through the upper portion of the lens, making them suitable for driving. 

Varifocals have an advantage when you need to glance at the dashboard or satellite navigation, because the intermediate zone covers that mid-range distance. 

Varifocals are also available as prescription sunglasses, which can be useful for driving in bright conditions or spending time outdoors. Depending on your personal preferences and vision needs, either of these lenses will give you the benefits you are looking for.