As we age, our ability to focus on close objects and images tends to deteriorate. This is the effect of presbyopia: a condition that worsens as we enter our 40s.

Presbyopia is a term that is unfamiliar to many people, but it is very common, especially among older people. Presbyopia develops when the lens of the eye ages and loses its flexibility. The eye’s natural ability to focus on objects at different distances is eventually inhibited by the loss of flexibility, leading to blurred vision and general difficulty seeing. For people with this part of the problem, lenses with multiple magnifications and multiple prescriptions need to be customised to suit their differences for near and far distances. Bifocal, trifocal and multifocal lenses were created, but their ability to treat refractive problems while also reducing presbyopia is the same. In this article, we focus on explaining the different uses of single vision and bifocal lenses as well as their advantages and disadvantages.

Single Vision Lenses

Single vision lenses are spectacle lenses used to correct a single vision problem, having the same prescription across the entire surface. They are typically used to correct nearsightedness or presbyopia, including astigmatism, and it is suitable for a wide range of conditions, providing sharper, clearer vision at a specific distance that suits your needs.

Digital single vision lenses are one type of single vision lenses that can improve your overall level of vision. Digital single vision lenses optimise your vision by eliminating distortion near the periphery of your field of vision and providing greater clarity when viewing through the lens. This type of lens is also more expensive than standard single vision lenses.

Advantages of Single Vision Lenses

• Simple design and easy to adapt: Single vision lenses have only one measurement, making it easier for people to adapt to the use of single vision lenses, even if you’ve never worn glasses before
• Provide clear visual: Single vision lenses provide greater visual clarity and quality, improving the overall standard of living.
• Wide range of visual effects to choose from: Single vision lenses can be customised as photochromic transition lenses, anti-blue light lenses or sunglass polarized lenses. For example, anti-blue light lenses can help protect your eyes from the harmful blue light produced by all digital screens (laptops, tablets and mobile phones).
• Lower cost: Single vision lenses are usually more affordable than progressive multifocal lenses.

Disadvantages of Single Vision Lenses

• Limited vision correction: Single vision lenses can correct refractive errors and give you clear vision at a certain distance, but for people with different vision needs (such as presbyopia or strabismus), monofocal lenses may not be convenient enough and require multiple pairs of glasses or frequent changes.

Bifocal Lenses

Bifocal lens is a lens with two refractive powers that corrects vision at two focal lengths to improve your distance and near vision (read). The bottom portion will have a prescription that allows you to see nearby objects more clearly, and the top portion allows you to focus on objects that are farther away.

There are several types of bifocal lenses available, such as flat top bifocal, blended bifocal, transition bifocal lenses, executive bifocal lenses. Different types of lenses can provide customers with different usage scenarios.

Need For A Bifocal Lens

• Myopia Correction: Bifocal lenses correct myopia and make distant objects visible.
• Presbyopia correction: Bifocal lenses also correct presbyopia, making near objects visible. Presbyopia is the loss of focus of the eyes on near objects that occurs with age.
• Driving: Bifocal lenses can provide a convenient solution for people who need to see the dashboard and the road in the distance clearly while driving.
• Reading: The near vision focus of bifocal lenses makes them ideal for reading, making close objects such as books and magazines clearly visible.
• Computer use: although bifocal lenses are mainly used for distance and near vision correction, they can also be used for working on a computer. However, specialised computer lenses may be more appropriate for people who use computers for long periods of time.

Pros of Bifocal Lenses

• Versatility: Bifocal lenses can correct both myopia and presbyopia for different vision needs.
• Convenience: Instead of having to spend money on two different types of glasses, only one pair of glasses is needed for different vision needs.
• Cost-effective: Bifocal lenses are considered to be cheaper than progressive lenses and can achieve the same vision correction as progressive lenses.
• Highly selective: The lens material can be tailored to the customers’ comfort level, and the customers can ask to add an additional layer of anti-reflective, blue-light-filter and photochromic filters.

Cons of Bifocal Lenses

• Distracting Bifocal Lines: The centre focus of a bifocal lens may not be as sharp as a monofocal lens, which may affect the quality of vision for some specific activities, such as using a computer. The extreme contrast between the two prescription types can often annoy and distract consumers.
• Acclimatisation period: Since bifocal lenses require adaptation to two focal points, this may cause some people to experience eye irritation or dizziness when they start using them.

Which Type of Lens Would Be Right For You?

Age

If you’re under 40 and don’t have any problems other than nearsightedness or farsightedness, monofocal lenses may be the way to go. But if presbyopia begins to set in at age 40, carrying around and switching between two monofocal lenses from time to time can be a headache, and that’s when you’ll need a pair of bifocal lenses to meet your vision needs!

Lifestyle

Everyday activities have a significant impact on your vision needs. If you’re out and about and just need to see the surrounding scenery, single vision lenses will meet your needs, but if you’re driving or using a computer and need to switch between distance and near vision frequently, bifocal lenses will be more suitable for you!

Adaptability

Adjusting to bifocal lenses can take some time, especially for first-time glasses users. If you don’t want to go through an adaptation period, you may prefer single vision lenses.

Budget

In general, bifocal lenses tend to be more expensive. Considering budget constraints is also an important factor in choosing the right lenses for you.