眼睛里的漂浮物是什么？

What are those floaty things in your eye?

词汇：考研 | 句法：六级| 文本：考研

刘立军供稿

Have you ever noticed something swimming in your field of vision? It may look like a tiny worm or a transparent blob, and whenever you try to get a closer look, it disappears, only to reappear as soon as you shift your glance. But don’t go rinsing out your eyes! What you are seeing is a common phenomenon known as a floater.

你是否曾经注意到视野中有东西在游动？它可能看起来像一条小虫子或一个透明的斑点，而每当你试图仔细看时，它却消失了，只有在你转移视线时又重新出现。但别急着去冲洗眼睛！你看到的是一种常见的现象，称为“飞蚊症”。

The scientific name for these objects is Muscae volitantes, Latin for "flying flies," and true to their name, they can be somewhat annoying. But they’re not actually bugs or any kind of external objects at all. Rather, they exist inside your eyeball.

这些物体的科学名称是Muscae volitantes，拉丁语意为“飞舞的苍蝇”。正如其名，它们确实有些烦人。但它们并不是虫子，也不是任何外部物体，而是存在于你的眼球内部。

Floaters may seem to be alive, since they move and change shape, but they are not alive. Floaters are tiny objects that cast shadows on the retina, the light-sensitive tissue at the back of your eye. They might be bits of tissue, red blood cells, or clumps of protein.

“飞蚊”看起来像是活的，因为它们会移动并改变形状，但实际上，它们并不是生物。“飞蚊”是投射在视网膜（眼球后部对光敏感的组织）上的微小物体。它们可能是组织碎片、红细胞或蛋白质团块。

And because they’re suspended within the vitreous humor, the gel-like liquid that fills the inside of your eye, floaters drift along with your eye movements, and seem to bounce a little when your eye stops.

由于它们悬浮在玻璃体（一种充满眼球内部的凝胶状液体）中，“飞蚊”会随着眼球的运动而漂移，并在眼球停止移动时似乎轻轻弹跳。

Floaters may be only barely distinguishable most of the time. They become more visible the closer they are to the retina, just as holding your hand closer to a table with an overhead light will result in a more sharply defined shadow.

大多数时候，“飞蚊”几乎难以察觉。它们越靠近视网膜，就越明显，就像将手靠近桌面时，在顶灯下会产生更清晰的阴影一样。

And floaters are particularly noticeable when you are looking at a uniform bright surface, like a blank computer screen, snow, or a clear sky, where the consistency of the background makes them easier to distinguish. The brighter the light is, the more your pupil contracts. This has an effect similar to replacing a large diffuse light fixture with a single overhead light bulb, which also makes the shadow appear clearer.

当你注视一片均匀明亮的表面时，比如空白的电脑屏幕、雪地或晴朗的天空，“飞蚊”尤其显眼，因为背景的一致性让它们更容易被分辨出来。光线越亮，瞳孔收缩得越多。这种效果类似于用一盏顶灯替换大面积的散射光源，这也会使阴影变得更清晰。

There is another visual phenomenon that looks similar to floaters but is in fact unrelated. If you’ve seen tiny dots of light darting about when looking at a bright blue sky, you’ve experienced what is known as the blue field entoptic phenomenon.

还有另一种视觉现象看起来与“飞蚊”相似，但其实并无关联。如果你在注视明亮的蓝天时看到有微小的光点在飞舞，那么你经历的就是所谓的“蓝场内视现象”。

In some ways, this is the opposite of seeing floaters. Here, you are not seeing shadows but little moving windows letting light through to your retina. The windows are actually caused by white blood cells moving through the capillaries along your retina’s surface.

在某些方面，这与看到“飞蚊”正好相反。这里，你看到的不是阴影，而是让光线透过的小“窗口”。这些“窗口”实际上是白细胞沿着视网膜表面的毛细血管移动造成的。

These leukocytes can be so large that they nearly fill a capillary causing a plasma space to open up in front of them. Because the space and the white blood cells are both more transparent to blue light than the red blood cells normally present in capillaries, we see a moving dot of light wherever this happens, following the paths of your capillaries and moving in time with your pulse.

这些白细胞可能会大到几乎填满毛细血管，从而在它们前面形成一个血浆空间。由于这些空间和白细胞对蓝光的透明度比毛细血管中的红细胞更高，因此无论何时发生这种情况，我们都会看到一个移动的光点，沿着毛细血管的路径移动，并与脉搏同步。

Under ideal viewing conditions, you might even see what looks like a dark tail following the dot. This is the red blood cells that have bunched up behind the leukocyte.

在理想的观察条件下，你甚至可能看到光点后面有一个类似暗尾的东西。这是堆积在白细胞后面的红细胞。

Some science museums have an exhibit which consists of a screen of blue light, allowing you to see these blue sky sprites much more clearly than you normally would.

一些科学博物馆设有蓝色光屏展览，让你能够比平时更清楚地看到这些“蓝天精灵”。

While everybody’s eyes experience these sort of effects, the number and type vary greatly. In the case of floaters, they often go unnoticed, as our brain learns to ignore them. However, abnormally numerous or large floaters that interfere with vision may be a sign of a more serious condition, requiring immediate medical treatment.

虽然每个人的眼睛都会经历这类现象，但其数量和类型差异很大。对于“飞蚊”来说，它们通常会被忽视，因为大脑学会了忽略它们。然而，如果“飞蚊”数量异常多或体积过大，干扰了视力，则可能是某种严重疾病的征兆，需要立即就医。

But the majority of the time entoptic phenomena, such as floaters and blue sky sprites, are just a gentle reminder that what we think we see depends just as much on our biology and minds as it does on the external world.

但大多数时候，像“飞蚊”和“蓝天精灵”这样的内视现象只是温和地提醒我们，我们所“看见”的内容不仅取决于外部世界，也取决于我们的生物学特性和思维。

【词汇】

1. blob n.（不规则的）斑点，团状物

2. retina n. 视网膜

3. clump n. 团块，聚集物

4. vitreous humor n. 玻璃体液，玻璃状液

5. entoptic adj. 眼内的，内视的

6. leukocyte n. 白细胞

7. capillary n. 毛细血管

8. plasma n. 血浆，等离子体

9. sprite n. 小精灵，幽灵

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