Back to Health and Wellness

How Do Glasses and Contacts Correct Your Vision?

Posted on April 9th, 2015

You probably know dozens of people who wear eyeglasses—you may even wear them yourself. In fact, it’s estimated that only four out of every ten people have perfect vision, which means that 60% of Canadians are in need of some form of vision correction. And yet, despite this statistic, most of us who wear glasses or contacts everyday don't really understanding how they work.

Below are a few facts on the science behind how glasses and contacts correct your vision.

How Do Your Eyes Focus?
At the very back of your eye is the retina, which is composed of a series of complex cells. The retina reacts to light and transmits that information to the brain, letting you see a final image. The retina does this by making the image smaller (not unlike how a digital camera previews an image), focusing the light, and curving the image to match the natural shape of your eye. To further help in the process, the eye has a lens between the retina and the pupil (the "peep hole" in the center of your eye that lets light into the back of the eye) and a transparent covering known as the cornea (the front window). 

What Makes Vision Blurry?
When light enters into the eye, the cornea and lens work together to focus the image onto the retina. The retina then sends the image to the brain, which is essentially how we see. When you suffer from nearsightedness, farsightedness, or astigmatism, it means something is wrong with either the lens or the cornea. When you see an optometrist , they will determine your prescription based on how much more light needs to be bent in order to give your brain a focused image. And just like that, the blurriness is gone when you put on your glasses or contacts.

How Do Corrective Lenses Work?
Corrective lenses are designed to help the lens and cornea create a clear image for the retina to send to the brain. The prescription in your glasses adjusts how the light hits the eye so that, in combination with the lens and cornea found in your eyes, your vision is clear. Eyeglass lenses bend the light more or less, depending on the strength of your prescription.

How Do Internal Freeform Lenses Make a Difference?
Internal Freeform lenses use technology that fuses the prescription onto the back of the eyeglass lens using three-dimensional digital software (as opposed to other lenses, in which the prescription is added to the front of the lens). Because the prescription is closer to the eye it offers a wider field of view and much less distortion. This technology also takes into account the individual movements of your eyes, how far your lenses sit from your eyes, and the natural curvature of your face.

The best way to determine what type of corrective lenses you need is to schedule an appointment with an optometrist. Remember that your vision often changes over time, which is why it's recommended by Health Canada that you get an exam at least once every two years (and once a year for children, the elderly or individuals suffering from health problems).

To get your vision tested and learn more about how your eyes work, book an appointment with an FYidoctors location near you.