What Are Bifocals and How Do They Work?

What Are Bifocals and How Do They Work?

Admit it. You don’t even like to say the word. “Bifocals,” while an important piece of vision correction, are sometimes taken to be synonymous with old age. No one wants to admit they need them, and if you do need them, you’re probably not telling a soul. 

Somewhere along the timeline of human existence and eye care, we collectively decided that bifocals meant you were over the hill. The reality is that bifocals are an important technology that helps correct vision issues at any age. 

If your eye doctor has recently given you the not-so-great news that multifocal lenses are in your future, don’t be alarmed. The science of vision correction has advanced, and there are much better zero-line lenses available to give you the vision correction you need without any flack from your slightly younger contemporaries.

First, let the team of eye safety experts at Stoggles drop some knowledge about basic vision correction and why you’d need multifocal lenses instead of single-vision lenses. 

What Are the Basics of Vision Correction?

Each year when you get your eyes checked (and if you aren’t getting your eyes checked every year, you should be), your doctor gives you a prescription for vision correction (if you need it) so you can visit your optician and get corrective eyewear. 

Different prescriptions correlate to different types of vision issues, called refractive errors. The most common types of refractive errors are myopia, hyperopia, astigmatism, and presbyopia. 


Myopia is the most common type of refractive error that your optometrist or ophthalmologist corrects. It’s also referred to as nearsightedness or near vision. This means you can see text and objects close up but have difficulty seeing objects and text from far away. They may appear out of focus or blurry.


The opposite of myopia is hyperopia. This refractive error is also referred to as farsightedness or distance vision. A person with farsighted vision can see objects far away with clarity but has trouble seeing objects or text close up. 

Keep this one in mind, because we’re going to cover another one in a moment that sounds similar.


If you have astigmatism, you have a cornea that is misshapen. This makes it difficult to see both close up and far away. Bright lights also complicate vision issues for a person with astigmatism. It can be virtually impossible to drive at night because of the appearance of halos or starbursts around oncoming headlights or street lamps. 


Like hyperopia, presbyopia makes it hard for you to see objects that are close up, but the underlying cause isn’t a genetic issue or the shape of your lens. Presbyopia is caused by aging. In fact, you could add it to the list of things that are “sure bets” in life: death, taxes, and presbyopia. 

Most people begin experiencing symptoms of presbyopia around middle age, but you can show signs of age-related vision decline as early as your 30s. 

To correct these vision issues and bring your vision back into focus, you need corrective eyewear. One type of corrective eyewear is bifocal glasses. If you’re not ready for the rocking chair and thick glasses just yet, you’ve got options. 

What Are the Main Types of Corrective Lenses?

If you’re looking at the eye prescription your doctor handed you after your comprehensive eye exam, you probably aren’t going to see something as simple as “Hey, you’ve got presbyopia, you need bifocals” written on the paper. Instead, you’ll see boxes and abbreviations that tell your optician exactly how to customize your lenses for your vision needs. 

Some people have single vision issues that can be corrected with a single vision lens. That means your lens will correct your vision at one single distance. For instance, if you only have trouble seeing close up, you might be wearing a pair of reading glasses to read this article. Basic reading glasses are usually single-vision lenses that correct your vision solely at a closer range.

For the rest of us, there are multifocal lenses. These help correct vision issues that happen at different distances. So, what happens if you’ve had myopia your entire life and then develop presbyopia? You’d need vision correction from both near and far distances, and that’s where bifocals come in. 

The Beef With Bifocals

History accredits Benjamin Franklin with the invention of bifocal lenses. While we are eternally grateful for them (and for electricity), the bifocal glasses he developed had two distinct partitions. The top of the lens corrected distance vision, while the bottom of the lens corrected near vision. 

The visible line denoting the two separate vision corrections made it obvious the wearer had on a pair of glasses that were more than single vision correcting. Not to mention, they were often visible to the wearer.

There was also another issue that bifocals couldn’t address. What if you had a need for three correction distances? 

Trifocal Lenses

One of the most important developments made upon Ben Franklin’s bifocals was the invention of the trifocal lens The trifocal lens solved two problems:

  1. A person with multiple fields of vision that needed correction could now experience clear vision with a single pair of eyeglasses.
  1. The annoying line in the middle of the glasses was now gone.

Early trifocals weren’t without their own issues, though. They featured a tiny half moon on the bottom half of the glasses. The top half of the glasses corrected for distance, while the top part of the half moon corrected for intermediate vision, and the lower part of the lens corrected for near vision. This trifocal-style lens was also developed into safety eyewear.

Safety Eyewear With Vision Correction

Early safety eyewear was thick, heavy, and bulky. It also offered little in terms of vision correction. As technology advanced, the D segment lens became an option for workers like mechanics, who needed vision protection and correction on different distance fields. These glasses were difficult to wear, uncomfortable, and hard to learn to use. 

Like both bifocals and trifocals, they required the wearer to train their eyes to use a certain part of their glasses depending on what they were looking at. For example, if you need to view something in the distance, you’d need to gaze out of the top of your glasses. 

Thank the optical gods for additional discoveries because we now have two alternate options to bifocals and trifocals that are low-profile and allow for eyeglass lenses that are crystal clear. We’ve also got some updates for safety eyewear, too.

What Are Some Modern Eyewear Options?

Three types of modern eyewear have replaced the need for bifocals, trifocals, and bulky safety glasses. 

Progressive Lenses

These lenses work like bifocals or trifocals, correcting vision at multiple distances and with different optical powers, but they have zero visible lines. The lens is crystal clear and as thin as a pair of single vision lenses. These lenses are typically easier to use because they have a gradual gradient between the different lens powers. This can make switching from near vision to far vision a seamless transition. 

Blended Readers

Readers (also known as cheaters to those of us who use them in lieu of seeing an eye care professional for a custom prescription) are now available with similar lens technology. Blended readers offer two sections within a lens without a visible line. This makes it easy to keep your reading glasses on while you’re also watching television or looking at something far away. 


Let’s face it. Protective safety eyewear hasn’t changed much since its invention. Many options are still big, hyper-masculine, and bulky, leaving many people to opt out of wearing safety eyewear even when they need it. 

Stoggles changed the game by developing a hybrid style of protective eyewear that is a cross between your favorite modern glasses and the protective safety glasses you need. The best part? We offer progressive lenses and reading options if you need vision correction.

Allow Us To Introduce Ourselves

Jobs that require protective eyewear beg for eyewear options that are comfortable, lightweight, protective, and stylish. Stoggles checks every box by offering all the safety features you need in styles and colors that are unexpected and fresh.

Every pair of Stoggles comes preloaded with features that protect your eye health.

ANSI Z87.1-2020 Certification

Your safety eyewear should be able to take a hit, and Stoggles can. Our lenses are ANSI Z87.1-2020 certified, which means they can withstand high-speed impact without shattering and sending shards of material into your eyes.

Side and Top Shields

The sides and tops of regular eyeglasses leave your eyes vulnerable. We protect those areas with top and side shields. These low-profile shields keep your eyes safe on all sides without distorting your vision correction prescription (if you have one).


Fogging lenses are a drag, and keeping your eyewear clear is one way we keep your eyes safe and your shirt tails tucked in. Our lenses are all coated with a state-of-the-art anti-fogging compound so that your eyewear stays fog-free no matter how steamy your situation. 

UV Blocking

Ultraviolet light can damage your eyes and cause age-related vision issues to happen sooner. UV protection does not correlate to the depth of shading on your lenses either. In fact, you can have a dark pair of shades that don’t offer much in the way of actual UV protection. 

Stoggles are all created from lightweight polycarbonate material, which is naturally UV-blocking without any shade. If you do want to throw a little shade, Stoggles Sun Polarized or Dimmers have you covered.

Blue Light Blocking

While we’re talking intrusive light, let’s cover blue light. Blue light comes from the sun, your computer, your phone, LED televisions, and probably aliens. Okay, not really aliens, but the exposure to blue light is pretty consistent and comes from numerous sources. Protecting your eyes from it requires specialized eyewear that filters it out. 

All Stoggles have blue light-blocking filters manufactured directly into the lenses of the eyewear. Stoggles gives you all these features plus some of the most surprising frames and colors you can imagine. 

Forget Old Foggy Eyewear

Bifocals are so last century (sorry, Ben). At Stoggles, we offer both blended readers and prescription lenses, making your journey to finding the perfect eyewear that much easier. Upgrade your eyewear and elevate your eye safety with Stoggles, the impeccably-dressed safety eyewear that protects your vision and your style. 


Astigmatism, Hyperopia, and Myopia | Boston Children's Hospital

What Is Astigmatism? Symptoms, Causes, Diagnosis, Treatment | American Academy of Ophthalmology

Presbyopia | National Eye Institute

The invention and early manufacture of bifocals | PubMed

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