You're listening to Brains On, where we're serious about being curious.
Brains On is supported in part by a grant from the National Science Foundation.
I want to take you back to a time, in the early 90s, when I was in third grade.
Third grade Molly loved school.
I loved school. My teacher was the beloved Miss A, who made school fun.
We got to keep pet rocks on our desks.
Mine was named Rosie.
Good morning, Rosie.
We read funny books out loud.
Once upon a time, there was a little old woman and a little old man who lived together in an old house.
They were lonely, so the little old lady decided to make a man out of stinky cheese and rotated through classroom jobs.
My favorite classroom job was a weather reporter, where you got to announce the weather forecast to the class every morning.
Today will be cools with a 25 % chance of snow.
One day, we switched desks.
It was good because I got to sit next to my friend Maggie, but our desks were as far away from the whiteboard as you could be and still be in the classroom.
One day, Miss A was writing on the board with an orange marker, but I couldn't see anything.
Excuse me, Miss A, but I think your marker's out of ink.
But the marker wasn't out of ink.
It was working perfectly well.
I just couldn't see it.
Miss A told my parents that she thought I needed glasses, and she was right.
I went to the eye doctor, got my prescription, and picked out some frames and waited for the glasses to be ready.
When I finally got to wear my glasses for the first time, I was amazed.
Wow. Everything was so crisp and clear, and I still remember how floored I was by the trees.
The trees, they have leaves.
I mean, I knew trees had leaves before I got glasses, but they had just looked like fuzzy greenness on top of a trunk.
And I thought that was just how trees looked.
But then I got glasses.
I can see each individual leaf.
They're moving a little in the breeze.
And there's a bird sitting on that branch, too.
Getting glasses changed my life, and I can't wait to show you today how cool glasses are.
Because they're really super duper extra cool.
You're listening to Brains On from APM Studios.
I'm your host, Molly Bloom.
And I'm here with my co -host, Lucita from Bellingham, Washington.
Hi, Lucita. Hi, Molly.
And Lucita, you wrote into us with a question.
Yeah, I wrote, why do some people need glasses?
So, Lucita, are you part of the some people that need glasses?
Yeah, I am. So how old were you when you got glasses?
I was actually same age as you.
Third grade. Oh, my gosh.
So how did you know that you needed glasses?
Well, I started getting really painful headaches after school and the word started looking really, like, it can't seem easy, but fuzzy when I looked at them really close.
So I told my mom and yeah.
And so are things close up blurry or things far away blurry to you when you're not wearing your glasses?
Close up. OK. And so when you put your glasses on, how do they help?
It makes it so I don't have really painful headaches when I'm reading.
And after I'm stop reading and if I look really, really close at the paper, like, if I looked at the script really close without my glasses, it would start to kind of blurry.
But with my glasses, it wouldn't.
Nice. And do you wear them all the time or just when you need to read something?
I use them when I need to read something, but like I might get a stronger prescription.
Yeah, that's the thing about getting glasses is that when I was growing up, I had to go to the eye doctor every year and get my eyes checked.
And pretty much every year my eyes got a little bit worse.
So I needed to change the prescription of my glasses.
So what grade are you in now?
I'm going into fourth grade.
OK, so you've had glasses for about a year now.
Yeah. And what do your glasses look like?
Well, my glasses are shade green around the lenses.
And then going back, like the part that connect those on my ear is tortoise shell cat.
Oh, do you love them?
I do specifically because my cat is tortoise shell.
So it reminds me of my kitty.
Oh, that's so cool.
So before we can find out how glasses work and why some people need them, we need to talk about eyes.
There's beautiful orbs right in the middle of our heads.
And here's a hot drawing tip.
When you're drawing an oval for a face, the most realistic spot for the eyes is right in the middle between the top and the bottom of the oval.
Yeah, our foreheads are much bigger than we think.
Too true. But back to our eyeballs.
Here are the basics of how we see.
Light enters the eye and hits the back of the eyeball.
Then a nerve takes a message from there to the brain.
And the brain reads that message.
It's pretty incredible.
Light is bouncing off all the objects around me and all that light travels into my eyeballs.
Then my brain takes that information and shows me the world.
It's wild stuff. OK, so let's break down how all the parts of the eye work together.
Lucida, can you describe what an eye looks like from the outside?
Well, you have this white part and then you have the color of your eyes.
The iris, I'm pretty sure, is what it's called.
And then you have your pupil, the black dot in the middle of your eye.
Nice. Yeah. So there's that white part, like you said, then the colored ring and the black dot.
And one of the most fun things about making brains on is that when we're researching and finding answers to listener questions, sometimes I learn facts that help me see the world in a whole new way.
Like this one, that black part of your eye, Lucida, it isn't black at all.
It's actually a hole.
What the what? Yeah, right.
That's what I said, too.
It looks black because it's dark inside your eye.
So we see it as black.
But that black part is the hole where light enters your eyeball.
So cool. That hole is called the pupil.
And the color part is called the iris.
Like I said earlier.
Yes. And it's the iris's job to make that hole in the middle, the pupil, bigger or smaller.
That lets more or less light into your eye.
Right. So when I'm in a dark room, my pupil gets bigger to get as much light to the back of my eye as possible.
And when it's really bright out, my pupil gets smaller.
When I was younger, I would stand in front of a mirror and turn the light off and watch my pupil get bigger.
And then I would turn the light back on and watch it shrink down again.
You know how to have fun.
I sure do. OK, back to eyeballs.
Over the top of the colored iris and the black pupil is a clear dome.
It protects the eye and focuses the light coming in on the back of the eyeball.
That dome is called the cornea and getting that light focused is so important that there's another clear layer behind the iris called the lens.
The lens also helps focus the light in the right spot on the back of the eye.
So to recap, there's the iris, the colored part, the pupil.
That's the hole that light gets in the cornea, the clear dome on the top of the eye and the lens that's behind people.
And then at the very back of the eyeball is a tissue paper thin layer called the retina.
The retina takes all the light around you and turns into a message that your brain can read.
So if you don't need glasses, your eye works something like this.
The cornea focuses the light through the pupil, through the lens and it hits the retina at the back of your eye.
Sometimes the light doesn't get focused in the right spot.
This can happen for a bunch of reasons.
It could be the shape of your cornea, your lens or even the whole eyeball itself.
The way these parts are shaped changes where the light is focused inside your eye.
Different people need glasses for different reasons.
Here's one example.
Light enters your eye, the cornea focuses the light through the pupil, through the lens and it hits in front of your retina instead of on it.
When that happens, things far away look blurry, but close up things are clearer.
That's called being near sighted because your near sight is strong.
I'm near sighted, so it's easy for me to read a book without glasses, but I need my glasses to see the whiteboard.
There are other reasons why someone might need glasses.
Like the shape of your eye might cause the light to be focused behind your retina instead of on it.
When that happens, things close up look blurry.
That's called being far sighted because your far sight is strong.
So if you can see things far away well, but close up is blurry, that's far sighted.
Right, so the name for the way you see is named after your strength.
I appreciate that focus on the positive.
Me too. So to recap, when things look blurry, that's because the light isn't being focused on the right spot on the back of the eye.
So if that's the problem, how does blurry vision get fixed?
Focusing the light in the right spot.
Exactly, and that's what glasses do.
Since the lens in my eye and my cornea can't get the light focused on the right spot on their own, my glasses are here to help.
The curve of my glasses focuses the light right where it needs to be, so I can see clearly when I wear them.
Contacts work the same way.
They add some extra curve so that light gets focused where it needs to go, the retina.
That's very cool, but why do I need glasses and some of my friends don't?
Great question. We're going to answer it in just a bit, but first, it's time for us to focus on the mystery sound.
Are you ready for the mystery sound?
Honestly, not, but I will do it.
Do you find the mystery sound tricky?
Yeah, it's a lot of pressure.
You know what? I would say most listeners don't get them right.
I hardly ever get them right, so I would not worry about it one little bit, but here it is.
I would say like a bee or something or someone winding something up and then letting it go.
That's really good ears.
Do you want to hear it again?
I have no idea what this is either.
It's weird. It sounds like a bee robot thing, but I know that's not what it is.
I mean, who knows? These mystery sounds are always so tricky.
I mean, one time there was frozen hot dogs being banged together.
Exactly. You never know what it's going to be.
Let's hear it again.
Okay, what do you hear now?
Someone pulling a trigger on one of those mini helicopter things that aren't really helicopters, like those blades, rolling it back and then letting it go.
You know what I'm talking about?
Yeah, I totally do.
Yeah, it does sound like a toy of some sort with like something being like wound up.
Yeah, and then letting go or a robot bee.
Yeah, it could be a robot.
We just don't know.
Okay, we're going to hear it again.
We've got another chance to guess and hear the answer at the end of the show.
So stick around. We're working on an episode all about animal leadership, and we want to hear from you.
What animal do you think would make an excellent leader?
What qualities do you think are important for a leader to have?
What could our human leaders learn from this animal?
Would you nominate a cheetah because they can move super fast?
Or a blue whale because it has a loud voice everyone will want to listen to?
So Lucida, what animal do you think would make a great leader?
My cat because she's just awesome.
Oh, I love that. So is she the leader of your family?
She is very protective of me and follows me around everywhere.
And she's loving. Honestly, she doesn't respect any of us because no cats really do, but she loves us.
And I think having self -esteem and loving the people you're taking care of is some qualities a leader needs to have.
Nice, excellent answer.
Well, listeners, we want to hear from you.
Record your answer and send it to us at brains -on .org slash contact.
While you're there, send us your mystery sounds, drawings, and questions.
Like this one. Why do we have tongues?
You can find the answer to this question on the Moment of Umm podcast, a short dose of facts and fun every weekday.
Find Moment of Umm and more at brains -on .org.
So keep listening. Brains On Universe is a family of podcasts for kids and their adults.
Since you're a fan of Brains On, we know you'll love the other shows in our universe.
Come on, let's explore.
Entering Brains On Universe.
To find my favorite podcasts.
Brains On. Smash Boom Best.
Forever ago. Picking up signal.
Forever ago. The History Show hosted by Joy Dolo.
Welcome to... Joy's Hall of Stalls.
Every door in this hall leads to a different model of toilet from throughout history.
You want a potty like it's 1999?
Right this way. Zorp.
Where did the signal go?
Must find Forever ago.
Now! Listen to Forever ago, wherever you get your podcasts.
Brains On. You're listening to Brains On.
I'm Lucita. And I'm Molly.
So far we've learned the eye is taken light.
And it gets far more than ever.
It's focused on the back of the eyeball on the retina by the cornea and the lens.
If that light isn't focused in the right spot, your vision will be blurry.
Glasses and contacts help by focusing the light in the right spot on the retina.
But everyone who needs glasses has unique eyes, which means we need different kinds of help from our glasses.
Like I need help seeing things clearly close up.
And I need help to see things clearly far away.
So, Lucita, have you been to the eye doctor before?
Yes. I have been twice.
And what do you remember about your eye exam?
Well, the first time I looked at a weird house through a lensy mob, a lensy mobob thingy mobobber.
I don't know what they're called.
I didn't need glasses the first time.
But then the second time, I looked at a bunch of letters on a board.
And the smaller they got, they looked blurry.
Like I thought the O was a random blob in the Q2 and some of the Ks.
Yeah. So a lot of times when you go to the eye doctor, you have to look at those letters and try to read them.
And sometimes they are blurry if you need glasses.
You know, I know we've had a lot of listener questions about going to the eye doctor.
Like, why do you have to get special drops?
What are those letters?
How does it work? So to help get answers to all these questions, I hung out with Dr.
Sarah Stroul from the University of Minnesota while she was with a patient.
It's Dr. Stroul. Do you remember me?
No. It's been a while.
That's okay. It's been a long time.
You've grown up so much.
I'm your eye doctor.
I'm going to be taking a look at your beautiful eyes.
I see you already met my friend Molly.
Here's Dr. Stroul while she was with her patient, seven -year -old Allie from Minnesota.
Why don't I take a look and we can talk about your eyes and answer any questions you have.
Would that be okay?
Do you remember how we do that?
It's super easy. I'm going to take a look with a flashlight.
