What are bifocal reading glasses?

For many people, turning 40 brings vision changes, most commonly, presbyopia — age-related loss of the ability to see close up. This can be a daunting change for those who already rely on corrective lenses. If you need help seeing both far and near, bifocal reading glasses can provide the perfect solution. These lenses have one zone for seeing objects far away and another for reading fine print up close.

How do you know if you need bifocal readers? Your eye doctor can conduct a vision test to determine what sort of correction you need. If you struggle to see far away and to make out those tiny letters at the bottom of the vision test, you’re a candidate for bifocals.

Cost-conscious shoppers can opt for non-prescription reading glasses — bifocal or otherwise. This inexpensive option just might meet your vision needs. However, according to the American Academy of Ophthalmology, if you have eye issues such as astigmatism or different vision in each eye, you’ll probably need custom glasses, as cheap bifocal reading glasses might not meet your needs. Read on to learn about your choices.

How do bifocal reading glasses work?

Bifocal lenses have two zones. The top part of the lens helps you see things in the distance, while an area in the bottom half of the lens is designed for reading. 

This lower portion of the bifocal lens reduces the effort it will take for your eyes to focus on receipts, smartphone screens, menus and other nearby objects. 

Why bifocal reading glasses?

These types of lenses are typically prescribed for adults age 40 and older to correct presbyopia, which is the inability of the eyes to focus on close-up items. Presbyopia is different from farsightedness. This condition is a normal part of aging — even healthy adults with perfect vision experience this vision loss as they grow older. 

Presbyopia is treatable with glasses. And while the problem grows gradually worse over time (until around age 50-55), it won’t completely rob you of your vision. If you also need correction for distance vision, bifocal readers can offer the correction you need. The bifocal prescription combines your single-vision correction with a new correction for reading.

Bifocal reading glasses aren’t only for adults, however. In some cases, doctors prescribe bifocals to children who have trouble focusing and suffer eye strain when reading. Children and young adults who need prescription glasses typically are recommended single-vision lenses. These lenses correct the wearer’s nearsightedness, farsightedness or astigmatism.

SEE RELATED: Can reading glasses ever help see distance?

How do I use bifocal lenses?

Bifocal reading glasses require the wearer to look up through the distance portion of the lens when focusing on a faraway object. When reading or focusing on something within 18 inches of your eyes, you look down and through the bifocal segment of the lens.

One warning: Bifocals require a period of adjustment. You’ll have to get used to things such as walking down stairs — bifocal readers might force you to adjust the angle of your head. However, most people eventually grow accustomed to wearing bifocals all the time.

Types of bifocal lenses

To find the best bifocal reading glasses for you, you’ll need to know a bit more about the types of lenses and frames available. Bifocal lenses generally are designed the same way. A small area in the lower part of the lens corrects your near vision. The rest of the lens enhances your distance vision.

Bifocal lenses are sold in an array of shapes and sizes. Smaller, narrower lenses can function well with weaker prescriptions. For stronger prescriptions, you may need larger lenses as it takes more space to accommodate the entire prescription. If you choose a bifocal lens that’s too small, you could experience a prism effect or optical distortion.

In bifocal readers, the segment of the lens devoted to correcting near vision takes one of several shapes:

• A half-moon — also known as a flat-top, straight-top or D segment

• A round segment

• A narrow rectangle, also called a ribbon

• The full bottom half of a bifocal lens, called the Franklin, Executive or E style

Your eye care practitioner can guide you to the lens design best suited to your vision needs.

What about that line on the lenses?

You will notice that the lenses on bifocals have visible lines where the two types of vision correction meet. The line in a round-segment bifocal is usually less pronounced than the line in flat-top and Executive styles.

It is possible to buy no-line bifocal reading glasses — a product called an “invisible bifocal.” This is a round-segment bifocal lens with the visible line buffed out. There is a downside, however — removing the line can distort the wearer’s view.

Types of frames for bifocal reading glasses

You can choose from a large range of frames for your bifocals. The choice depends, in part, on how you expect to use your glasses. Plastic frames come in a wide variety of colors, styles and prices. However, they’re less durable, meaning they might be better for indoor or limited use. 

If you plan to wear your bifocals while working or exercising outdoors, consider a more durable frame. Metal, titanium or alloy frames can withstand more wear and tear. Titanium is the most flexible and lightest material for eyeglass frames. No matter which material you choose, be sure they comfortably fit your face, nose and ears.

What type of lens material should I choose?

The lenses in your bifocal reading glasses likely won’t be made of glass but, rather, some type of plastic. Polycarbonate lenses are the most popular option. This material is lightweight and resists breaking, so if you spend a lot of time outdoors, polycarbonate lenses might be the right choice. 

The list doesn’t end there, however. Trivex is an alternative that’s both light and impact-resistant. And this material can create less optical distortion than polycarbonate.

For bifocal wearers with more intense prescriptions, high-index plastic lenses are a slim, lightweight alternative. With their thin profile, high-index plastic lenses can reduce the unflattering appearance of thick-lens glasses.

Protective coatings can help your bifocals last longer

For prescription bifocal glasses, you have several choices for protective coatings.

• Anti-scratch coatings improve the durability of your glasses. Most plastic lenses, including polycarbonate and Trivex, are prone to scratches, so this coating can protect your investment.

• Anti-reflective coatings cut glare and distracting reflections on the surface of your glasses. This type of coating is especially important for wearers who are very nearsighted and need high-index lenses, as this material is more likely to create problematic glare.

• Photochromic lenses protect your eyes from harmful UV rays. Also known as transition lenses, these tinted bifocal reading glasses darken automatically in sunlight. This is beneficial if you will wear the glasses outside, or if you’re particularly sensitive to sunlight.

If you choose custom glasses, your optician can help you choose the protective coating(s) that match your needs.

At what age will I need bifocal reading glasses?

Presbyopia strikes four million Americans each year, according to the University of Illinois College of Medicine. There’s no single age for the onset of presbyopia. The condition can start as early as the mid-30s and as late as 50. 

If you don’t use prescription glasses, you’re likely not to notice presbyopia until your mid-40s. If you’re farsighted, you’ll notice the loss of up-close vision a bit earlier. Health conditions, including diabetes, can hasten the onset of presbyopia.

Will reading glasses weaken my eyes?

This is a common concern. However, the fear is unfounded. Reading glasses won’t cause your sight to diminish more quickly with age. Unfortunately, no medication or exercise can stop presbyopia either. Presbyopia is simply agre-related loss of ocular elasticity that makes it harder to focus on small print. Delaying the switch to bifocal reading glasses will do nothing to prevent age-related deterioration of your up-close vision.

For most people, the eye’s natural lens continues to grow less flexible from the ages of 40 to 60. Less flexibility means less ability to focus. As a result, many people continue to adjust their eyeglass prescriptions during these decades.

What if I spend a lot of time at a computer?

Bifocal readers are designed to help you see things in two ranges — objects more than 20 feet away and things within arm’s reach. Computer screens can fall into a no man’s land for bifocals — the screen might be just far enough away that the bifocals don’t help. 

Some people opt for a dedicated pair of computer glasses — a single-vision prescription designed for the computer screen’s distance. Others choose trifocals or progressive lenses, which can correct intermediate-distance vision as well as close-up and far-away vision. Trifocals have clear lines between the three types of correction, while progressives promise a seamless transition.

What if I need bifocal safety glasses?

For workers in some trades, regular bifocal reading glasses might not provide the protection you need. If you work as a carpenter, plumber, mechanic or machinist, you need to see up close, but you also need more impact protection than someone who uses bifocal readers at a desk job. 

For the best protection, choose safety eyewear with a high impact rating. The lenses will include the manufacturer's trademark and a “+.” The frame will be marked "Z87-2" on the inside of the front and temples.

Should I save money with non-prescription bifocal reading glasses?

There’s nothing wrong with economizing on your readers. Prescription bifocals are likely to set you back $200 or more. On the other hand, you can buy non-prescription bifocal readers for $50. If you’re apt to break or lose your glasses, or if you simply like to wear different glasses for different situations, over-the-counter glasses let you build up a collection on the cheap.

To test a pair of non-prescription glasses in a store, try grabbing a box with a label or a magazine, and then heading to the rack with the glasses. Try a few different pairs and see which ones best allow you to read. 

You’ll also want to test your distance vision with the glasses. It is worth noting, though, that these off-the-shelf glasses might not address your unique vision needs. The cheaper lenses can also come with side effects such as glare, color distortion and optic distortion.

Are bifocal readers worth it?

If you’re in your 40s and you already needed vision correction before age-related presbyopia set in, bifocal reading glasses can correct both vision problems. You’ll be able to see near and far with one pair of glasses. Bifocals are convenient — rather than switching between glasses throughout the day, you can address two vision issues with one pair of glasses. 

On the other hand, bifocal readers might not be much help if you do most of your reading on screens that are more than arm’s length away. 

Nearly everyone will need reading glasses as they age. Whether you need bifocal reading glasses depends on your vision and lifestyle. If you’re uncertain, talk to an eye doctor about whether bifocal lenses are right for you.

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Page published on Tuesday, February 16, 2021