How does laser eye surgery work? - Dan Reinstein

翻译人员: Yuxin Zhang 校对人员: Gabriella Hu

In 1948, Spanish ophthalmologist Jose Ignacio Barraquer Moner

1948 年， 西班牙眼科医生

何塞 · 伊格纳西奥 · 巴拉奎尔 · 莫纳 （Jose Ignacio Barraquer Moner）

was fed up with glasses.

受够了戴眼镜。

He wanted a solution for blurry vision that fixed the eye itself,

他想要找到修复眼睛本身的方法 来解决视力模糊的问题，

without relying on external aids.

而无需依靠外部帮助。

But the surgery he eventually devised was not for the faint of heart.

但他最终设计的手术方案 并不适合胆小的人。

Barraquer began by slicing off the front of a patient’s cornea

巴拉奎尔通过切下患者前侧眼角膜，

and dunking it in liquid nitrogen.

并将其泡在氮液中。

Using a miniature lathe, he ground the frozen cornea

通过使用微型车床， 他将冰冻的眼角膜

into the precise shape necessary to focus the patient’s vision.

磨成能够让病人 视力聚焦的精准形状。

Then he thawed the disc, and sewed it back on.

接着，他把这个圆盘 解冻后再缝合回去。

Barraquer called this procedure keratomileusis,

巴拉奎尔把这种手术称为： 角膜磨镶术，

from the Greek words for “carving” and “cornea.”

源自希腊语中的 “雕刻” 和 “角膜”。

And though it might sound grisly, his technique produced reliable results.

这虽然听起来很可怕， 但他的技术却十分可靠。

So how did Barraquer’s surgery work?

那么，巴拉奎尔的手术 是如何操作的呢？

Keratomileusis corrects what are called refractive errors:

角膜磨镶术矫正了所谓的屈光不正，

imperfections in the way the eye focuses incoming light.

即眼睛无法将射入的光线 完美地进行对焦。

Ideally, the cornea and lens work together to focus light

理想情况下，角膜和晶状体共同作用

on the surface of the retina,

将光线聚焦再视网膜表面上，

but several kinds of refractive errors can impair this delicate system.

但是几种屈光不正 会破坏这个精巧的系统。

In people with myopia, or short-sightedness,

在近视的人群中，

a steep cornea focuses light just short of the retina.

较陡的角膜使得聚焦的光线 刚好无法抵达到视网膜。

Those with hyperopia, or far-sightedness, have the opposite problem:

远视的人则有刚好相反的问题：

light is focused too far beyond the retina.

光线聚焦在远超过视网膜的地方。

And in people with astigmatism, the cornea has two different curvatures

而患有散光的人， 角膜有两个不同的曲率

which focus light at two distances and produce blurry vision.

使光线有两个不同的聚焦点， 造成视力模糊。

Even those with perfect vision will eventually suffer from presbyopia,

即使视力完美的人， 最终眼睛也会老化，

or “aging eyes.”

即 “老花眼”。

As the proteins in the lens age, they slowly increase its size.

随着晶状体中的蛋白质老化， 它们会慢慢变大。

By an adult’s mid-40’s, the lens is too large

成年人到了四十岁左右， 晶状体由于太大

to easily change shape and shift focus.

而不易改变形状和转移焦点。

Glasses and contact lenses bend light to compensate for these refractive errors.

眼镜和隐形眼镜会改变光线方向 以补偿这种屈光不正。

But, as Barraquer’s procedure shows,

但是，如同巴拉奎尔的手术所表明

we can also alter the shape of the cornea itself;

我们也可以改变角膜本身的形状，

moving the focal point backwards, forwards,

将焦点向前或向后移动，

or pulling a divided image together.

或让分离的图像重叠回到一起。

And thankfully, modern eye surgeons can sculpt the cornea

幸好，现代眼科手术可以使用

with far less invasive tools.

创口更小的工具雕刻角膜。

In corrective laser eye surgery, surgeons rely on excimer lasers.

在激光矫正眼科手术中， 外科医生依靠准分子激光器。

These tools are accurate enough to etch words into a human hair.

这些工具精准到 可以在人类的头发上刻字。

To safely accomplish these ultra-fine incisions,

为了安全地完成这些超精细切割，

they use a technique called photoablation.

他们使用一种叫做光消融的技术。

This allows the laser to essentially evaporate organic tissue

基本上，这种技术 使用激光让有机组织蒸发，

without overheating surrounding eye tissue.

而不会让周围眼组织过热。

So how does laser eye surgery actually work?

那么，激光眼科手术 到底是怎么运行的呢？

The first step is to separate a thin layer from the front of the cornea.

第一步是将角膜前侧 分离出薄薄的一层。

This can be done with either a flat, wide blade, or a femto-second laser

这既可以使用平宽的刀片，

也可以使用飞秒激光。

that produces millions of tiny plasma bubbles

它可以产生数 百万个微小的等离子气泡，

to create a plane beneath the corneal surface.

在角膜表面下形成一个平面。

Surgeons then lift the flap to expose the inside of the cornea.

接着，外科医生会将角膜瓣掀开， 露出角膜内部。

Guided by the refractive error and the shape of the cornea,

根据屈光偏差和角膜形状

the excimer laser robotically sculpts the exposed corneal bed

准分子激光会自动将暴露的角膜床

into the correct shape.

雕刻成正确的形状。

This process usually takes less than 30 seconds for each eye.

这一过程对于每只眼睛 通常只需要不到 30 秒。

Finally, the flap is closed,

最后，将角膜瓣放回原位，

and its edges reseal themselves in just a few hours.

只需几小时，它的边缘会自然地愈合。

Because the lasering is done on the eyeball itself,

因为激光手术是在眼球上进行，

it’s described as “in situ,” or “on site.”

这在手术中被称为“原位”的，

Its complete name is “laser in-situ keratomileusis” –

全称为“准分子激光原位角膜磨镶术”，

but you probably know it as LASIK.

但大家熟知的可能是“LASIK”。

Essentially, this technique carves a patient’s contact lens prescription

基本上， 这项技术是将患者的隐形眼镜处方

onto their cornea.

直接刻到其角膜上。

Like any surgical procedure,

和其他任何外科手术一样，

LASIK comes with certain risks.

LASIK 手术也伴随着风险。

Some patients experience slightly blurred vision that can’t be corrected by glasses.

有些患者会出现轻微的视线模糊，

且无法通过佩戴眼镜矫正。

But the technique is currently about as likely to damage your eyes

但这项技术目前对于眼睛的伤害

as wearing daily disposable contact lenses for one year.

如同佩戴一年的日抛型隐形眼。

Today, a technique called SMILE enables surgeons to sculpt the cornea

如今，外科医生通过一项名为 SMILE 的技术来雕刻角膜，

through even smaller incisions –

通过更小的切口，

further reducing recovery time.

进一步缩短了恢复的时间。

And lasers aren’t just correcting the three types of refractive errors –

激光手术不仅可以 矫正三类屈光不正，

this technology can also restore aging eyes.

这项技术还可以修复老花眼。

In a technique called Laser Blended Vision,

有一种叫做激光混合视觉的技术，

surgeons adjust one eye to be slightly better at distance vision

外科医生微调一只眼睛， 使其远距视线更好，

and the other to be better at close range vision.

然后微调另一只眼睛， 使其近距离视线更好。

The difference between the two eyes is small enough

两个眼睛之间的区别足够小到

that most patients can merge their vision,

使大部分患者可以合并视线，

allowing both eyes to work together at all distances.

让两只眼睛可以一起看不同的距离。

Advances in laser technology continue to make vision correction surgery

激光手术的持续进步，

more effective and accessible.

使得视力矫正手术更加高效和便利。

One day soon, Barraquer’s vision of a world without glasses

巴拉奎尔的愿景： 一个没有眼镜的的世界，

may finally come true.

在不久的将来，或许将会实现。