At some point growing up, my vision changed.
And slowly I stopped being able to see past about...
this far in front of my face.
Basically, anything past...
like 10 inches in front of my eyes...
is blurry.
So eventually I got glasses
and with them my world turns from this...
to this.
This whole experience
as inconvenient as it is...
is more widespread than it's ever been.
[overlapping] “-Myopia.” “-Myopia.”
[overlapping] “- Myopia, am I saying it right?” “-A rise in short-sightedness...”
“...and the researchers actually called it an epidemic...”
“...but they're still trying to figure out why this is...”
Rates of myopia or near-sightedness
or needing glasses to see things far away...
have been rising for decades.
In the US, where I live
just 25% of people were myopic in 1971.
By 2004, that number was up to 42%.
And if current trends continue
it’s estimated that half of the world's population
will be myopic by 2050.
In Hong Kong, Singapore, Taiwan and South Korea
rates are already a lot higher than that.
And a growing portion have high myopia
which the WHO categorizes as a prescription stronger than -5.
That puts them at risk of losing their sight one day.
For decades, researchers thought
that whether or not you needed glasses
was just a matter of genetics.
And it partly is.
Having one myopic parent doubles your odds
of being nearsighted
and having 2 increases the odds 5 fold.
But human genetics don't change this fast.
The abruptness of this increase suggests that
that this change is environmental.
Something about the way we live today
is making it harder and harder
for people to see at a distance.
So what could it be?
Most people are born
with eyes that are too short from front to back.
In this shape, the lens focuses images behind the retina.
That's the light sensitive tissue at the back of the eye.
That makes the eye hyperopic or farsighted.
Blurry up close and clear from far away.
But as we grow up, our eyes grow too.
Until they reach a spherical shape.
In this shape, the lens focuses light directly
onto the retina and produces a clear image.
But sometimes the eye keeps growing longer.
In this shape, the lens can focus up close images onto the retina.
But at a distance, images focus at a point
in front of the retina...
making distance vision blurry.
So all of us with myopia
just have eyeballs that have grown too long.
The eye does not look like a basketball anymore.
It looks more like a rugby ball.
That's Seang Mei Saw.
She's a myopia epidemiologist and physician in Singapore.
It is a lifelong disease
so once you're myopic, it doesn't regress.
So what's making more and more people’s eyes
grow longer than they should?
The evidence points to the way
we spend time in childhood and adolescence.
That's when our eyes grow fastest.
So it's when most people's myopia develops
and then stabilizes.
Though it can develop later
if you abuse your vision enough.
Two factors in particular have the biggest influence.
Near work or the time that we spend looking at things up close...
and how much time we spend indoors.
In a healthy eye, muscles have to squeeze the lens
in order to focus up close images onto the retina.
So some experts theorize that if your eyes grow up
straining to look at things up close
a lot of the time, they'll just grow longer
to reduce that strain.
But the evidence on this explanation is mixed.
The stronger explanation is time spent indoors.
Exposure to bright outdoor light
stimulates the production of dopamine in the retina.
This neurotransmitter regulates the eyes growth...
without enough dopamine
the eye doesn't know when to stop growing
and indoors it's hard to get enough.
The light from the sun
has up to a 100,000 lux on a sunny day.
Whereas in the room the light levels generally
and only about 200 to 300 lux.
But between electronic devices and early emphasis on academics...
eye experts believe that children today
are growing up with a combination of too little daylight
and too much time doing things up close.
And nowhere is that more apparent
than in East and Southeast Asia.
Children in Asia are not spending that amount of time outside.
This could possibly be because of the education system
has become much more competitive.
The children have a lot more work.
They attend teaching centers
and you spend more time reading and writing.
Needing glasses or contacts to see for the rest of your life
is obviously inconvenient.
But in the long term
the consequences of that distorted eyeball shape
can become serious.
University of Houston Professor of Optometry
Mark Bullimore, explained this to me.
You know, you're born with a finite amount of tissue
that make up the various coats of your eyeball.
Excessive elongation of that quite simply
places additional stress on those structures.
The retina has been stretched so much that starts to break
and then sort of peel off like an old piece of paint.
The longer those eye structures are stretched
the higher the risk of disorders
like myopic macular degeneration, retinal detachment...
glaucoma and cataracts.
So we're finding this almost linear relationship between them.
The amount of myopia and the risks to your vision...
later in life.
We used to think about myopia as an optical defect.
Now we think about it much more as a disease.
And the earlier a child becomes myopic
the more serious their myopia can become
and the greater the risk of debilitating conditions.
Which means it's important to intervene as early as possible.
So, what does that look like?
For those who start to develop myopia
there's treatment.
First are multifocal, soft contacts, and glasses.
They make peripheral vision intentionally blurry
which appears to slow the progression of myopia.
Then there's orthokeratology or ortho-k lenses...
hard contact lenses worn only at night
that reshape the wearer's cornea while they sleep...
so that they can see at a distance during the day.
And there are atropine eye drops
low doses of a substance that temporarily paralyzes
the eyes’ focusing muscles
which seems to reduce the development of myopia.
But the first line of defense is prevention.
The simplest and most effective way to prevent myopia
is to get kids to spend more time outside.
In Taiwan, the government introduced
a nationwide program in 2010, encouraging schools
to get students outside for 2 hours every day.
It appears to have successfully reversed
a 40 year-long increase in myopia rates.
And since 2001
Singapore has funded public education promoting time outdoors...
and conducted annual vision screenings at schools.
And it seems to be working.
Right now, these rates may be higher than ever
but the future of myopia will only look like this
if we keep doing things the same way.
And we've never been in a better position
to change.