What Are These Glasses For Anyway?

Updated: Apr 28, 2020

My glasses need a good cleaning.

To help build a base for better understanding, and to help set up future blog topics (like laser vision correction) let’s get back to basics for today’s blog! A lot of times, people bring in their glasses to their exam and generally, patients know that they need glasses to help them see better, but often they don’t even know if they’re nearsighted, farsighted, or what the term “astigmatism” really means!

So here’s a little more background information, and the next time you get your eyes checked, you can make sure that you and your doctor are seeing eye-to-eye (boom, eye pun quota reached!).

Refractive Error

A refractive error is a type of vision problem that makes things appear blurry. This happens when the shape of your eye causes light to focus improperly onto your retina (a layer of tissue at the back of your eye that captures visual images). Refractive errors are the most common type of vision problem, but there are still many people who don’t realize that they have it and how easily it can be corrected. Fortunately, in most cases, refractive errors can be corrected with glasses, contact lenses, or surgery. There are 4 common types of refractive errors, let’s break these down, shall we?

Nearsightedness (myopia)

If you have trouble seeing street signs or other far away objects like the blackboard, you likely have myopia. More commonly known as “nearsightedness” or “shortsightedness”, myopia is a condition that makes distant objects blurry. In myopia, the eyeball is typically elongated, so light is bent and focused in front of the retina instead of directly onto the retina. Often, people who are nearsighted will squint at things that are far away to make them seem more clear.

Farsightedness (hyperopia)

This condition is the opposite of myopia, and instead, the eye is biased to see things more clearly in the distance, while near objects are blurry or take more effort to see properly. In this case, the eyeball is often shorter, causing the light rays to bend and focus behind the retina instead of on the retina. Interestingly, this condition often goes undiagnosed in kids and younger patients because they are particularly good at compensating for their farsightedness. If left unchecked, sometimes this can cause unnecessary eyestrain, headaches, and difficulties with concentration.


While the name of this condition sounds scary to some, it’s quite common and easily corrected just like nearsightedness or farsightedness. People with astigmatism might experience blurriness or distortion for both distant and near objects, and this is due to an asymmetric curvature of the front of the eye (or cornea). Sometimes, doctors will describe the eye as “football-shaped” rather than perfectly curved like a basketball. Glasses or contact lenses can be prescribed with the opposite curve to cancel this out and make images more clear.


Presbyopia is an age-related condition where the main symptom is a decrease in the ability to see things clearly up close. As we age, the natural lens in our eye thickens and loses elasticity, which reduces our ability to change focus from distant to near objects. Often, people with presbyopia will pull away from their reading material in order to compensate for this. Heads-up: this might be the first sign that you are ready for reading glasses! While this change is generally dreaded, there are both customized glasses and contact lens options that can be helpful with this transition and often can help your symptoms more than the standard off-the-shelf, ready-made reading glasses.

What are the symptoms of refractive error?

While the most common symptom of a refractive error is blurry vision, other symptoms can include:

  • Squinting

  • Headaches

  • Dizziness

  • Eye strain

  • Trouble focusing when doing visually-demanding activities

  • Double vision

  • Seeing a glare or halo around lights

These symptoms are not always obvious, so it’s important to get your eyes checked regularly. If you already wear glasses or contact lenses and are still experiencing these symptoms, you might need an updated prescription. I gonna need glasses?

Depending on how much refractive error is present, correction with glasses or contacts lenses will be needed in order to see clearly. Do you take after your mom or your dad more? A sibling perhaps? Your risk of having a refractive error is greater if you have family members who require glasses or contact lenses. And for most people, even if they have previously never required glasses in their lives, presbyopia usually starts to appear at around 40 years of age and older. Your eye doctor can tell you more about your risk and how often you should be checked.

By Dr. Peter Chan, OD.

with contributions from Marie Ubungen

Stay tuned for future posts where we’ll discuss vision problems related to your overall health. In the meantime, read up on our post about healthy eye foods, and if you haven’t had your eyes checked in a while, why not use our handy exam request form and make an appointment with one of our friendly optometrists?

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