Glasses have been designed to help our eyesight and protect our eyes from the sun. But did you ever wonder why some people have to wear glasses to see properly while others don’t? Before we can figure that out, we need to know how the eye works. First, let’s take a look at the retina, which is the part of the eye that reacts to the light of anything you look at and sends all this information to your brain. Once the information reaches your brain, it can transform this into the image that you actually see! The retina has a curved surface because your eyes are round in shape and when you actually look at something, three things need to happen:
- The image you see must be reduced in size to fit onto the retina.
- The scattered light must come together and come into focus at the surface of the retina.
- The image must be curved to match the curved surface of the retina.
The eye also has other parts that work together and interact to make sure that all of these things happen! Two of the main ones are:
- The pupil, which is almost like a little peep hole in the middle of your eye that allows all of the light into the back of your eye.
- The cornea, which could be considered as the front window of your eye and acts as a transparent cover for your pupil.
These two parts work together in order to focus the image of what you are looking at onto your retina. There are many reasons why people might need to wear glasses – the cornea may not be shaped properly, causing blurred vision, or the surface of the cornea may not be smooth and lead to distortion of vision.
Types of vision distortion include myopia (nearsightedness), which happens when people can’t see very far ahead and distant objects appear blurry. Hyperopia (farsightedness) happens when people can’t focus properly on things that are close to them. Different types of glasses or lenses are needed to correct these and bring sight back to normal.
Inquiry – Digging Deeper
Do you wear glasses or lenses? If so, do you know why you need to wear these? Here’s a fun online eye test that you can do in class and get a better idea of what type of vision you have!