Curious Kids: How Do Glasses Help You See?
Jason Yosar, 23 Jan 18
       

Glasses help people to see by focusing light onto the retina. Marcella Cheng/The Conversation, CC BY-NC-ND

This is an article from Curious Kids, a series for children. The Conversation is asking kids to send in questions they’d like an expert to answer. All questions are welcome – serious, weird or wacky!


How do glasses help you see? – Andy, age 5, Vincentia.


Hi Andy, and thank you for your question about glasses.

You’ve asked this at a very good time because more and more people are needing to wear glasses, including young children, and we don’t really know why.

Our eyes let us see because light enters each eye, and the eye then creates a message that goes to the brain.

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.

Both shortsighted and farsighted people need glasses to help them see clearly. Wikimedia Commons/Hackfish, CC BY

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.

They work by helping the eyeball to focus light onto the correct place, the retina. Marcella Cheng/The Conversation, CC BY-NC-ND

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 people, including young children, are needing to wear glasses. Flickr/Ryan McDonough, CC BY

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.

Most children in China are shortsighted and need glasses to see things far away. The Chinese government is so worried about this that they are making sure all students spend some time outdoors instead of just being inside the classroom.

Glasses can cost lots of money, and children who need glasses but don’t wear them don’t do as well in school. Once you need glasses, you usually need them forever - your eyes won’t go back to normal on their own.

Sign in to view full article

       
The Future of Online Advertising is Big Data and Algorithms
The challenge facing advertisers and advertising professionals is remaining relevant in the face of a fundamental technological change. Namely, algorithms ...
Rob Livingstone
Tue, 4 Apr 17
When Things Go Wrong In An Automated World, Would We Still Know What To Do?
We live in a world that is both increasingly complex and automated. So just as we are having to deal ...
Peter Fisher
Mon, 27 Mar 17
Is The Developed World We’ve Created Giving Us Cancer?
I had assumed that the small lump in my breast was a blocked milk duct from nursing my seven-month-old son. ...
Chelsey Kivland
Thu, 8 Jun 17
Use Your Body, Not WiFi, to Transmit Secure Passwords
Sending a password or secret code over airborne radio waves like WiFi or Bluetooth means anyone can eavesdrop, including hackers.
Jennifer Langston
Fri, 6 Jan 17
What If Several of the World’s Biggest Food Crops Failed at the Same Time?
Less than one-quarter of Earth’s total cropland produces nearly three-quarters of the staple crops that feed the world’s population – ...
Anthony Janetos
Thu, 8 Jun 17
An Epoch Times Survey
At Epoch Times, We Care :o)
Sports Elements
BUCHERER
Sports Elements
Sports Elements