The eyeball itself doesn’t actually “see” – the brain sees. The eyeballs just take pictures, like two little cameras. To see properly, each eyeball needs to send the light that enters it onto a very exact spot inside the eyeball, called the retina. If the light falls onto the wrong place, your vision will be blurry.
Many people don’t need glasses and can see just fine. This is because their eyeballs are focusing light properly onto the retina.
However, some people have eyeballs that are too long. They are called “shortsighted”. For these people, things far away, like street signs or the classroom blackboard, can look blurry.
Other people have eyeballs that are too short. They are called “farsighted” and things close to them, like a book or a mobile phone, can look blurry.
Both shortsighted and farsighted people need glasses to help them see clearly.
They work by helping the eyeball to focus light onto the correct place, the retina. Only then can the eye see clearly.
Maybe you have a grandma or grandpa who wears glasses whenever they are reading books or using their mobile phone. When people get older, they usually become a little bit farsighted because a part of their eye called the lens becomes stiff and doesn’t work properly.
More and more young people in the world are needing to wear glasses.
We’re not sure why, but some scientists think that children who spend too much time inside are more likely to need glasses. We don’t know if it’s because they aren’t getting enough sunlight or if they’re simply reading too much or playing too many video games when they get home.
