After this video I can officially diagnose you as a.
Licensed.
Uh amateur.
Optometrist.
So here's the game first ask your mom for a meter stick.
Mom can I have a meter stick sure here so I've got this meter stick and I put it on my eye.
Now this is always a little bit dangerous but you want to not put it through your eye but just next to.
Your eye and then hold your finger next to the meter stick C and run your finger down the meter stick closer.
And closer and closer until you can no longer Focus notice this hurts trying to focus on something really close hurts.
That's cool and then also.
So write down where it is that is the absolute closest that you can focus for me.
Today.
It looks like I can focus at let's check that out 13 cm away so that's called my near.
Point.
My near point is.
13.
Cm.
That's cool hopefully yours is a a little bit smaller as I age that will get further out.
Cuz I have to strain.
To get to focus that close in turns out that when you relax your eye those ciliary muscles relax and the lens.
Gets much much flatter and so you will be able to focus on something that is nearly infinitely far away which is.
Pretty awesome you have to work much harder to make the lens bulby let's get a picture of an eye up here.
Eyes are kind of I don't know what brown where is my brown.
Dang it all right so maybe your eye is green.
And the eye is pretty much a sphere and then there's this lens thing in here and you've got these muscles here.
That can change of course they're all the way around they can change the dimension of this lens.
And they can change the dimension of this Gloppy thing that's on top of the lens it's all kind of gross.
But the general idea is if I make an axis here and I say here's an object that I want to see.
I won't be able to see it unless I can cause an image to form exactly at my retina I need an.
Image to form right there because the retina is sort of like it's sort of like the sensor for your eye this.
Is where the information gets encoded and sent via a little pipe that's pretty cool this goes to the brain and then.
You can think about what you see.
So yes when your uh little brother told you that was that your little brother I don't know maybe it was your.
Sister who told you that you see stuff upside down and your brain flips it back over again that is completely correct.
On the back of your eye is an in inverted image of everything that's happening in your life and your brain keeps.
Track of all that and sorts it out for you maybe that happened when you were little and thinking about why things.
Weren't upside down as they seemed like they were or maybe you just got used to it maybe upside down is right.
Side up I don't know you think about that for a little bit but I've found my near point and now I.
Want to find my Far Point so people who don't have any problems with their Vision people who don't have any problems.
With their Vision can look really far away stare off into the distance and see stuff that's awesome and you know I.
Mean maybe you presume.
Unless you've seen me in class or you've uh seen the momentum videos you probably think I'm a pretty attractive guy so.
You'd be like yeah that doc Shuster he's a pretty attractive guy but can you imagine me with glasses look at this.
This used to be me just last year I used to wear glasses and I walk around like hey everybody.
And so I mean.
I dealt with that for many years.
And I know it's weird to wear glasses and I'm sorry if you have to wear glasses.
But.
I wore glasses because I was.
Myopic.
And that means that I couldn't see far away so if you are.
Sad face I wish you could see far away try the meter stick trick.
And put the meter stick not in your eye but next to your eye and bring your finger further and further away.
From your eye until you can no longer focus on it and that will Define your Far Point and the good news.
For me is my our point.
Is infinity and hopefully that's the case for many of you as well I had to get glasses when I went to.
Freshman year in college I was sitting in the back of the classes and they were big classes and I couldn't see.
The board so I realized they needed glasses so that probably happens to many people and I'm afraid that it might happen.
To you too dun D but you can get glasses to correct that the idea of someone who is myopic.
The idea is their Far Point is here for instance.
We could just Define some random location to be their Far Point and if they're looking at something that's beyond the Far.
Point the problem is the Rays from that thing come in.
And they get focused.
Too.
Early so these rays are all like.
And they form an image right here so one thing you can say to people who have glasses and who are myop.
Not everybody with um with glasses as myopic but most people with glasses who are you know 20 to 30 to.
15 or something people those age almost.
Us H what do I mean to say I don't quite know but I would bet that probably 90% of people ask.
An optometrist but I bet 90% of people with glasses who are not yet 50.
Have um have my optis.
Something like that again Ask an optometrist you can tell them your eyes too.
Big.
So the problem is if the eye were smaller then this lens would be perfectly sufficient so something Happ where your lens.
Didn't quite grow enough when you I don't know hit 17 or something that's what happened to me and your eye kept.
Growing and suddenly it could no longer Focus out there so you had too much correction and you can't relax your eye.
Enough to make this lens correct less so what you need to do instead is you need to get up in here.
With a uh seafoam.
Green what kind of lens do I want do I want this to converge closer or further away I want it to.
Converge further away so I need a diverging lens up in here someone who's my opic has a diverging lens problem is.
You can't start a fire with this so people like us it's no it doesn't make any sense when you land on.
A desert island to hit us over the head and steal our glasses cuz we still can't start.
Fires.
That sucks because this won't concentrate any Rays dang it okay but if we do this then what we'll be doing is.
We'll be causing.
The uh oh man if the image is if see sorry if the object is here.
What we can do is use this lens to create a virtual object.
Through the lens.
Which then.
Focuses.
Right here.
And we will get a nice.
Beautiful.
Focus.
Because of the lens right on the retina so what we're doing is we're creating a.
Virtual.
Object.
For this lens.
By virtue of the.
First.
Lens.
We move.
The virtual object into the Far Point for your eye so the eye now believes.
That there's an object within the Far Point you're moving something.
Wow you're moving something like a tree that you want to see that's many meters away within your Far Point which might.
Be 80 cm away so now the image of the tree is only 80 cm.
Away.
From this lens.
Is causing the image of the tree to be that far away and you can now see it that's awesome here there's.
Another type of problem you may think that myop ism is terrible and awful but the true freaks are the people whose.
Eyes.
Too much.
So let's get one of them out here and if their eye wait a second no I mean their eyes don't focus.
Enough so if your near Point what if your near.
Is uh 55 CM can you imagine holding a book 55 C from your eye we will all get there probably your.
Eyes generally.
Get less and less tough at getting this lens to get really bulbous.
Like this and those muscles have to work to do that and your muscles get tired and pathetic as you age so.
What I need to do if I am.
Hyperopic.
Check.
This.
If you.
Too late now you've got an object here.
That's close.
And the problem is the Rays coming in here will converge.
Back here.
These Rays converge back here and we're finding.
That uh well you're going to have a fuzzy image on your retina because the focus is way back here you need.
To help these converge so you put yourself a little bit of corrective Optics right in front what you're doing when you.
Put a converging lens in here is you're helping them to converge sooner so after this converging lens they're coming out a.
Little bit closer here and they're able with your pathetic eye to focus then right here and you do get a nice.
Happy image on your retina and that's awesome so we need a converging lens in order to help people who cannot see.
Things that are close and we need a diverging lens in order to help people who cannot see things that are far.
Away H anything else I should say about that well we can do some calculations but I don't think this is the.
Right video for that.
Uh oh I guess what I should say is if this is your near.
What do I mean to say.
Yeah no no no I want your near point to be here the reason you can't see this thing if you're hyperopic.
Is because.
Um you are.
It is Too Close to You compared to your near point so the action of this converging lens creates a virtual object.
That's out here at your near point or just beyond it hopefully it makes it right at your near point and then.
You can still focus on it so you want to hit these people over their head and steal their glasses because this.
Will start a fire when you're on a desert.
Island.
Also Al when you look at them you notice their eyes look really big through their glasses because it's a magnifying glass.
At that point you're looking through a magnifying glass at these people's eyes so they have cool coke bottle glasses and they're.
Like.
I.
Wow that's a big eye right and you're thinking that when you look at these people awesome.
I don't really know what this is but it looks pretty cool.
And they are um.
Spooky looking really.
Um sorry if you are hyperopic.
I feel for you I tell you what I will tell you a little story when I was about I don't know.
32.
Or 33.
Or something.
Doctors took me in and strapped me down and sliced off the top of my eyes they went like this with a.
Knife they went.
And left a little flap and then they peeled this.
Back.
And that was pretty awesome cuz I was awake and I was watching them and then once they had this peeled back.
They did this with both of my eyes the other eye was over here and they just uh oh oh there was.
This little uh lensy bit and stuff and they sliced off the very top layer.
And peeled that sucker back also there was a little bit still left here so it was a flap it was a.
Nice eye flap and once inside my eye they used a laser to vaporize parts of my eye which was kind of.
Creepy cuz I could smell my eye.
Melting.
It was actually um breathing I was breathing my eye.
Then.
They flapped it back down and put some glue in there maybe it was just water I don't know and they used.
A brush.
And they brushed my eye for a good while.
Until.
Maybe it looked like a broom yeah they.
Were.
And then I could see the next day in fact I could see 2020 it was even 2015.
It was amazing so you should consider getting laser eye surgery because for me it was an absolutely awesome thing but consult.
With your doctor don't make any decisions based on YouTube videos that would be silly.