Nearsighted vs. Farsighted: What’s the Difference?

Nearsightedness and farsightedness are two common conditions called “refractive errors.” You have likely heard about them before when discussing eye care and eyeglasses. These conditions fall into the same category as astigmatism, but they affect the eyes in different ways. Nearsightedness is much more common than farsightedness, but both are fairly similar in how they affect the eyes and vision. 

It can be helpful to understand the differences between nearsighted and farsighted vision, so you’re better able to recognize them and address them before they develop. This guide takes a closer look at what each condition involves, the causes, the major differences between the two, and how you can use eyewear to help.

Nearsightedness Explained

Nearsightedness, or “myopia,” is one of the most common eye conditions worldwide, and research even points to more cases occurring nowadays than compared to past years. But what is nearsightedness, and is it treatable?

Let’s break it down:

Nearsightedness is when you can see objects and words clearly when you’re close to them, hence the term nearsighted, but not when you’re farther away. You may notice blurry vision when looking in the distance, squinting more often when looking far away, difficulty reading signs while driving, and having to move your phone or reading material closer to read. 

Nearsightedness is common and is easily treatable. It often develops during people’s childhood and young adult years. It is characterized by squinting, excessive blinking, eye rubbing, and needing to move closer to see objects clearly.

Causes

What causes nearsightedness to begin with, and how does the eye react to that? Here are the basics of how nearsightedness occurs. First, let’s talk about how the eye works. There are two main aspects of the eye that allow it to focus and function, the cornea and the lens. 

The cornea lies on the very outermost surface of the eye and the lens which lies behind it.

The cornea is shaped like a dome, while the lens is shaped more like an oval. They are both clear structures that help the eyes focus by refracting the light we see, bending it so we can focus on items around us. 

Nearsightedness is a refractive error that occurs when the shape of the eyeball or cornea is curved in a way that affects how our eyes are able to bend light and focus. The eye is sometimes too long, or the cornea may have a curve that’s too steep. This results in nearsightedness, making distant objects blurry.

Farsightedness Explained

Farsightedness is much less common than nearsightedness, and it often develops at birth—genetics greatly influence who will develop this condition. Farsightedness is the opposite of nearsightedness and occurs when the eyes are able to see distant objects clearly, while nearby objects may be blurry and harder to focus on. Depending on the degree of farsightedness, it may be less or more severe. 

Causes

Similar to nearsighted vision, farsightedness is due to a refractive error in the cornea and lens of the eye. In this case, however, the cornea or eyeball is too short or not curved at a steep enough angle. When light enters the eye, it’s refracted incorrectly, so it has trouble focusing properly on the retina. Instead, it focuses slightly behind it. This results in the blurriness associated with farsightedness.

How You Can Tell

It’s fairly easy to determine whether you’re nearsighted or farsighted. First, test out your ability to see distant objects. You can try looking at road signs or looking at any objects farther than 10 feet away. If you have trouble focusing or if your view looks blurry, you may have nearsightedness.

To test farsightedness, try looking at objects close by. You can grab a book or hold any object close to your face. If you have trouble focusing here but can still see things far away, you may have farsightedness. If you are unclear about what you need in a pair of glasses, reach out to an eye care professional near you. 

Nearsightedness vs. Farsightedness: Biggest Differences

The most significant difference in nearsightedness vs. farsightedness is the way that the cornea and lens are shaped, which affects how light is refracted. For those who are nearsighted, their cornea and eyes are too long, resulting in light refracted in front of the retina. For those who are farsighted, their cornea and eyes are too short, so the light is refracted behind the retina. 

In either case, however, there are very similar symptoms. For instance, you may feel the same frustration and discomfort when trying to focus near or far, and both refractive errors experience blurriness when focusing on objects. 

A Guide to Choosing Glasses for the Nearsighted and Farsighted

While the two conditions can be frustrating to deal with and lead to discomfort if unaddressed, they’re very easy to correct with the right pair of lenses. Here’s a guide on how eyewear can help. 

Glasses can help correct nearsightedness and farsightedness through the shape of the lens. In other words, the lenses are shaped to help refract light directly into the retina, correcting the shape of the eye. 

Here’s a closer look:

How They Work

Lenses that can help nearsightedness are concave in shape and made to be thickest at the edges and thinnest at the center. This helps bend the light so that it reflects on the retina directly instead of in front of it. In the same way, lenses that can help farsightedness are convex in shape and are thickest in the middle and thinnest on the edges. 

How To Choose

Glasses for nearsightedness are labeled with a minus sign, and you’ll likely have to wear these all the time so you can focus on objects far away. These lenses will need to be prescribed by your eye care professional.

Reading glasses are used to correct farsightedness and are labeled with a plus sign to represent the strength of the lens. You can wear reading glasses when you’re reading or more often, depending on when you need them.

How can you find the right glasses for you? Here are a few general guidelines to start with.

First, you’ll need to determine what strength reading glasses you need. There are a few ways to do this:

  • Printable diopter chart: Using the printable diopter chart is an excellent method if you’re buying reading glasses online and aren’t able to try them on. Print this chart and hold it 14 inches away from your face. Make sure you aren’t wearing any type of reading glasses. Start reading the line at the top and continue down the list until you find a line you can read clearly and easily without reading glasses on. 

There will be a coordinating number with a plus sign next to it listed to the side, and this is the reading glasses strength you need. If you have varying vision needs in your right and left eyes, cover each eye and repeat the process twice to find the strengths you need. If you need a different strength in each lens, customizable reading glasses could be right for you. 

  • PowerFinder tool: You can also use our PowerFinder tool if you already have a pair of reading glasses and simply need to update them. Simply enter information about your prescription and reading glasses strength. Then, answer a few more questions so our PowerFinder quiz can analyze a new reading glasses strength for you. 

Finding the Best Lenses for You

Farsightedness is known for having different levels of severity. While one person may need a smaller reading glasses strength for your refractive error, another person may need a stronger one. At Readers.com we carry strengths ranging from +0.25 to +7.00, so there’s a pair of reading glasses for everyone

 

Sources:

 Why Has Myopia Become More Common? Pacificu.edu 

 Nearsightedness – Symptoms and causes | Mayo Clinic 

Farsightedness – Symptoms and causes | Mayo Clinic 

Do You Need Glasses if You’re Farsighted? | Vision Center