And slowly I stopped being able to see past about...

我能看清的距離越來約短，大約...

this far in front of my face.

離這麼近才看得清。

Basically, anything past...

基本上，所有超過...

like 10 inches in front of my eyes... is blurry.

我眼前 10 英寸的東西...都是模糊的。

So eventually I got glasses.

所以，最終我戴上了眼鏡。

And with them, my world turns from this...

戴上眼鏡後，我的世界從這樣...

to this.

變成了這樣。

This whole experience, as inconvenient as it is, is more widespread than it's ever been.

儘管戴眼鏡很不方便，但這情況比以往任何時候都更加普遍。

-Myopia. -Myopia.

-近視。 -近視。

- Myopia, am I saying it right? -A rise in short-sightedness...

-近視眼，是這麼說嗎？-近視比例上升...

-...and the researchers actually called it an epidemic.

-...研究人員實際上已稱其為一種流行病。

-...but they're still trying to figure out why this is.

-...他們仍在試圖弄清這一切的原因。

Rates of myopia, or near-sightedness, or needing glasses to see things far away, have been rising for decades.

近視，也就是需要戴眼鏡才能看到遠處東西的比例，這幾十年來不斷在上升。

In the US, where I live, just 25% of people were myopic in 1971.

在我居住的美國，1971 年時，只有 25% 的人近視。

By 2004, that number was up to 42%.

但到了 2004 年，這個數字卻上升到了 42%。

And if current trends continue it's estimated that half of the world's population will be myopic by 2050.

照目前趨勢，據估計，到 2050 年世上一半人口都將成為近視眼。

In Hong Kong, Singapore, Taiwan, and South Korea rates are already a lot higher than that.

在香港、新加坡、臺灣和南韓等地區，近視率已比這高上許多。

And a growing portion have high myopia, which the WHO categorizes as a prescription stronger than -5.

而且越來越多的人有高度近視，也就是據世界衛生組織定義近視超過 500 度的情況。

That puts them at risk of losing their sight one day.

這些人面臨的是有一天將失去視力的風險。

For decades, researchers thought that whether or not you needed glasses was just a matter of genetics.

幾十年來，研究人員以為視力好壞只與遺傳相關。

And it partly is.

是與遺傳相關。

Having one myopic parent doubles your odds of being nearsighted and having 2 increases the odds 5 fold.

父母中有一個近視的人，其近視機率會增加一倍，而雙親皆近視則會增加五倍的機率。

But human genetics don't change this fast.

但人類遺傳學不會造成這麼快的變化。

The abruptness of this increase suggests that that this change is environmental.

這突然的增長表明，這種變化導因於環境。

Something about the way we live today is making it harder and harder for people to see at a distance.

人們今日的生活方式正在使我們越來越難以看清遠處的事物。

So what could it be?

會是什麼原因呢？

Most people are born with eyes that are too short from front to back.

大多數人的眼睛天生前後距離都過短。

In this shape, the lens focuses images behind the retina.

這種形狀下，晶狀體會將影像聚焦在視網膜後方，

That's the light sensitive tissue at the back of the eye.

也就是位於眼睛後面的感光組織上。

That makes the eye hyperopic or farsighted.

這會造成遠視。

Blurry up close and clear from far away.

近看模糊，遠看清晰。

But as we grow up, our eyes grow too.

但隨著我們成長，眼睛也會跟著成長。

Until they reach a spherical shape.

直到它們變成球狀。

In this shape, the lens focuses light directly onto the retina and produces a clear image.

這種形狀下，晶狀體會直接聚焦到視網膜上，產生清晰的影像。

But sometimes the eye keeps growing longer.

但有時，眼睛會不斷變長。

In this shape, the lens can focus up close images onto the retina.

這時，晶狀體能將近的影像聚焦到視網膜上，

But at a distance, images focus at a point in front of the retina, making distance vision blurry.

但遠處的影像會被聚焦在視網膜的前方，使得遠處的畫面變得模糊。

So, all of us with myopia just have eyeballs that have grown too long.

所以，近視眼患者只是眼球長得太長了。

The eye does not look like a basketball anymore.

眼睛看起來不再像個籃球了。

It looks more like a rugby ball.

它看起來更像個橄欖球。

That's Seang Mei Saw.

這是蘇祥美。

She's a myopia epidemiologist and physician in Singapore.

她是新加坡的近視流行病學家兼醫生。

It is a lifelong disease,

這是種終生疾病。

so once you're myopic, it doesn't regress.

一旦近視了，就不會恢復。

So what's making more and more people's eyes grow longer than they should?

那麼，是什麼讓越來越多人的眼睛長得比正常的長呢？

The evidence points to the way we spend time in childhood and adolescence.

證據指向人們度過童年和青春期的方式。

That's when our eyes grow fastest.

那是眼睛生長最快的時段。

So it's when most people's myopia develops and then stabilizes.

大多數人都是在這時開始近視加深並定型的。

Though it can develop later if you abuse your vision enough.

雖然這段時間後，近視也可能在不當用眼下加深。

Two factors in particular have the biggest influence.

有兩個因素影響最深。

Near work, or the time that we spend looking at things up close, and how much time we spend indoors.

近距離看東西以及室內活動的時間長短。

In a healthy eye, muscles have to squeeze the lens in order to focus up close images onto the retina.

健康的眼睛中，肌肉必須擠壓晶狀體以便將近距離的影像聚焦到視網膜上。

So some experts theorize that if your eyes grow up straining to look at things up close a lot of the time,

所以一些專家推測，如果在眼睛發展時，經常用力看近處東西，

they'll just grow longer to reduce that strain.

眼睛就會拉長以減少這種壓力。

But the evidence on this explanation is mixed.

但關於這一解釋的證據不一，

The stronger explanation is time spent indoors.

更有力的解釋是待在室內過久。

Exposure to bright outdoor light stimulates the production of dopamine in the retina.

暴露在明亮的室外光線下能刺激視網膜產生多巴胺。

This neurotransmitter regulates the eyes growth.

這種神經遞質能調節眼睛生長。

Without enough dopamine, the eye doesn't know when to stop growing.

沒有足夠多巴胺，眼睛不知道何時該停止生長

In indoors, it's hard to get enough.

而在室內很難接觸到足夠的室外光。

The light from the sun has up to a 100,000 lux on a sunny day.

天氣晴朗時，太陽光會達到 100,000 勒克斯。

Whereas in the room, the light levels generally are only about 200 to 300 lux.

而在房間裡，光照程度一般只有約 200 至 300 勒克斯。

But between electronic devices and early emphasis on academics eye experts believe that

在充斥電子設備和對早期學術的重視下，眼科專家認為

children today are growing up with a combination of too little daylight and too much time doing things up close.

如今的孩子成長過程中，日光接觸實在太少，近距離視物時間又太長。

And nowhere is that more apparent than in East and Southeast Asia.

這一點最明顯體現在東亞和東南亞地區。

Children in Asia are not spending that amount of time outside.

亞洲兒童待在戶外的時間偏少。

This could possibly be because of the education system has become much more competitive.

這可能是由於教育環境競爭激烈的關係。

The children have a lot more homework,

孩子們有更多的作業，

they attend teaching centers,

去上補習班，

and you spend more time reading and writing.

花更多時間閱讀和寫作。

Needing glasses or contacts to see for the rest of your life is obviously inconvenient.

餘生中都需要戴眼鏡或隱形眼鏡明顯很不方便，

But in the long term, the consequences of that distorted eyeball shape can become serious.

而從長遠來看，這種眼球形狀扭曲的後果可能十分嚴重。

University of Houston, Professor of Optometry, Mark Bullimore, explained this to me.

休斯頓大學驗光教授馬克·布利莫爾向我解釋了這一點。

You know, you're born with a finite amount of tissue that make up the various coats of your eyeball.

人天生有的組織數量是有限的，這些組織構成了你眼球的各種外層。

Excessive elongation of that quite simply places additional stress on those structures.

過度拉伸很容易給這些結構帶來額外壓力。

The retina has been stretched so much that it starts to break,

視網膜被拉伸過度，就會開始斷裂，

and then sort of peel off like an old piece of paint.

然後像舊油漆一樣剝落。

The longer those eye structures are stretched the higher the risk of disorders

眼睛結構被拉伸的越長，患疾病的風險就越高。

like myopic macular degeneration, retinal detachment, glaucoma, and cataracts.

諸如，近視性黃斑病變、視網膜剝離、青光眼和白內障等疾病。

So, we're finding this almost linear relationship between them.

我們發現兩者之間幾乎是線性關係，

The amount of myopia and the risks to your vision later in life.

近視程度和晚年視力喪失的風險。

We used to think about myopia as an optical defect.

過去，我們認為近視是種視力缺陷。

Now, we think about it much more as a disease.

現在，我們更常將其視作一種疾病。

And the earlier a child becomes myopic the more serious their myopia can become

而且孩子越早成為近視眼，其近視程度就會更加嚴重，

and the greater the risk of debilitating conditions.

出現視力衰弱的風險也越大。

Which means it's important to intervene as early as possible.

這意味著儘早開始保護視力很重要。

So, what does that look like?

那麼，該如何實行呢？

For those who start to develop myopia, there's treatment.

對於近視人群，是有治療方式的。

First are multifocal soft contacts and glasses.

首先是多焦點軟性隱形眼鏡和眼鏡。

They make peripheral vision intentionally blurry, which appears to slow the progression of myopia.

這種眼鏡會故意模糊周邊視力，以助於減緩近視發展。

Then, there's orthokeratology, or ortho-k lenses,

然後是角膜塑形片，

hard contact lenses worn only at night that reshape the wearer's cornea while they sleep,

也就是夜間佩戴的硬性隱形眼鏡，幫助在睡眠時重塑佩戴者的角膜。

so that they can see at a distance during the day.

這樣他們在白天就可以看清遠處東西。

And there are atropine eye drops,

還有散瞳劑，

low doses of a substance that temporarily paralyzes the eyes' focusing muscles,

可以暫時麻痺眼睛聚焦肌肉的低劑量物質，

which seems to reduce the development of myopia.

似乎可以減緩近視發展。

But the first line of defense is prevention.

但第一道防線是預防。

The simplest and most effective way to prevent myopia is to get kids to spend more time outside.

預防近視最簡單有效的方法就是讓孩子多到戶外活動。

In Taiwan, the government introduced a nationwide program in 2010,

在臺灣，政府於 2010 年推行了一項全國計劃，

encouraging schools to get students outside for 2 hours every day.

鼓勵學校讓學生每天室外活動 2 小時。

It appears to have successfully reversed a 40 year-long increase in myopia rates.

此計劃似乎已成功扭轉了長達 40 年的近視率上升趨勢。

And since 2001,

而自 2001 年以來，

Singapore has funded public education promoting time outdoors

新加坡政府也資助公立學校以增進孩童戶外活動時間，

and conducted annual vision screenings at schools.

並在學校進行年度視力檢查。

And it seems to be working.

這似乎也正在發揮作用。

Right now, these rates may be higher than ever,

現在，近視率比以往任何時候都高，

but the future of myopia will only look like this if we keep doing things the same way.

但如果我們持續同樣的生活方式，近視率未來只會持續攀升。

And we've never been in a better position to change.

改變，從現在開始。