Eyeglasses come in a variety of types. This includes a single-vision lens with one power or strength over the entire lens, or a bifocal or trifocal lens with multiple strengths over the entire lens.

But while the latter two are options if you need a different strength in your lenses to see far and near objects, many multifocal lenses are designed with a visible line separating the different prescription areas.

If you prefer a no-line multifocal lens for yourself or your child, a progressive additional lens (PAL) might be an option.

PALs are a type of multifocal lens specifically for people who need corrective lenses to see distant and close up objects. To put it plainly, these lenses allow you to see clearly at multiple distances without a bifocal line.

The need for a progressive lens increases with age. By the age of 35 or 40, many people have difficulty focusing their eyes on nearby objects. This is known as presbyopia, and to compensate for this focusing problem, some people wear single-vision eyeglasses for distance, as well as reading glasses for close up.

While this approach can work, PALs provide a simpler, more convenient solution to age-related vision problems:

  • The upper section of a progressive lens provides the strength you need to see clearly in the distance.
  • The lower section provides the strength you need to see clearly up close.
  • The middle section helps you see clearly at intermediate or middle distances.

These lenses provide a gradual transition in strength from top to bottom.

Even though some people require progressive lenses as they become older, these lenses are also an option for children who need eyeglasses for bold nearsightedness and farsightedness.

Pros of progressive lenses

  • One pair of eyeglasses for everything
  • No distracting bifocal line
  • Modern, youthful glasses

Cons of progressive lenses

  • Takes time to adjust
  • Visual distortions
  • Higher cost

Progressive lenses aren’t only an option for correcting nearsightedness and farsightedness, they can also correct an astigmatism.

An astigmatism is when light doesn’t focus evenly on the retina due to an irregular shaped cornea, resulting in blurry vision.

Along with correcting vision problems, other advantages of a progressive lens include:

1. Only need one pair of eyeglasses

Some people find that a progressive lens is better than a single-vision lens because it allows them to see clearly at different distances without the need to carry a second pair of eyeglasses.

A progressive lens does the job of a single-vision lens and reading glasses, so that you only have one pair of glasses on hand.

2. No unsightly bifocal line

Progressive lenses offer the benefits of a multifocal lens without a multifocal line. And since there’s a gradual shift in lens strength with a progressive lens, you don’t have to deal with any sudden changes in clarity, which are common with multifocal lines.

3. Modern, youthful appearance

Bifocal and trifocal eyeglasses are sometimes associated with old age. So wearing eyeglasses with a bifocal line may make you feel self-conscious. You might feel more comfortable with a progressive lens since there isn’t a visible line.

While a progressive lens can provide “no line” visual clarity, it’s important to understand the disadvantages of these lenses.

1. You must learn how to see through the lens

Bifocals and trifocal lenses have a visible line, so it’s easier to determine where to look for clear vision. Since progressive lenses don’t have a line, there’s a learning curve, and it might take one to two weeks to learn the correct way to look through the lens.

2. Temporary vision distortions

The lower part of a progressive lens is magnified because it’s designed for reading. So if your eyes look downward when stepping off a curb or walking upstairs, your feet may appear larger and it can be difficult to gauge your step. This can cause stumbling or tripping.

You’ll need to train your eyes to look through the distant part of the progressive lens rather than the reading part to avoid problems while walking.

Progressive lenses can also cause peripheral distortion when moving your eyes from side to side. These visual effects become less noticeable as your eyes adjust to the lenses.

3. More expensive than single-vision lenses and bifocal lenses

Keep in mind the cost difference between progressive lenses, single-vision lenses, and bifocal lenses. Progressive lenses are more expensive because you’re basically getting three eyeglasses in one.

In addition, you’re paying for the convenience and extra time that goes into creating a multifocal eyeglass with no lines.

But given the convenience and simplicity of progressive lenses, some people feel that the extra cost is worth it.

Typically, these lenses are more expensive than a bifocal. For example, you could pay $260 for a standard progressive lens and only $105 for bifocals, according to Consumer Reports.

You’ll also pay more for a higher quality progressive lens. For instance, a high-index progressive lens might cost $350, whereas you might pay $310 for a high-definition progressive lens. And if you want a scratch-resistant progressive lens, the price can jump to $400.

Prices may also vary by region and eyeglass company. So it’s important to shop around and compare prices.

Buying online may be an option; however, it can also have some risks. To work properly, progressive lenses need to be measured to your eyes and that can be difficult to accomplish online.

You might also consider that a 2011 study by the American Optometric Association revealed that 44.8 percent of 154 glasses ordered online had incorrect prescriptions or safety issues.

For best results, consider working with a skilled optician who can help you choose the best frame and lens type for you.

Even though a progressive lens allows you to see near and far distances clearly, these lenses aren’t the right choice for everyone.

Some people never adjust to wearing a progressive lens. If this happens to you, you may experience constant dizziness, problems with depth perception, and peripheral distortion.

Plus, if you work on a computer, you may find that a regular progressive lens doesn’t provide the clarity you need at an intermediate distance.

Instead, you might require occupational or computer progressive lens, which provides a stronger strength for intermediate distances. This can reduce eyestrain and eye fatigue.

The only way to know if progressive lenses will work for you is to try them and see how your eyes adjust. If you don’t adapt after two weeks, your optometrist may need to adjust the strength in your lens. If problems continue, a bifocal lens might be a better fit for you.

Progressive lenses are perfect for nearsightedness and farsightedness, but there’s a learning curve and some people never adjust to these lenses.

To help your eyes adjust, wear your progressive lens as often as possible in the beginning. Also, get into the habit of turning your head to look at objects instead of moving your eyes from side to side. Peering out the side of the glasses can distort your vision.

When reading, however, move your eyes and not your head.

Eyeglass technology is always improving. So if you’re unable to wear a progressive lens today, you might be able to wear one in the future.