英读廊——人的眼睛为什么只有棕、蓝、绿或极少数红色的？

Why are human eye colours restricted to brown, blue, green, and in extremely rare cases, red, as opposed to other colours?

译为什么人眼的颜色仅限于棕色、蓝色、绿色，在极少数情况下，还有红色，而不是其他颜色？

单词eye [ahy][a?] n. 眼睛

单词colours 原型 colour（也可以写作color） ['k?l?] n. 颜色

单词restricted 原型：restrict [ri-'strikt][r?'str?kt] vt. 限制；约束

单词brown [broun][bra?n] adj. 棕色的；褐色的

单词blue [bloo][blu?] adj. 蓝色的

单词extremely [ik-'streem-lee][?k'stri?mli] adv. 非常；极其

单词rare [rair][re?] adj. 罕见的；珍贵的

单词opposed 这里是过去分词作形容词用，表示“相反的”， 原型：oppose [uh-'pohz][?'pz] v. 反对；对抗；使对立

Eye color is in the Iris, and the Iris has two layers, a back layer that's always fully pigmented, and a thicker front layer.

译眼睛的颜色在虹膜上，虹膜有两层，一层是完全着色的后一层，另一层是较厚的前一层。

单词layer ['ley-er]['le] n. 层

单词fully ['foo?l-ee, 'foo?l-lee]['f?li] adv. 十分地；完全地；全部

单词pigmented [p?ɡ'ment?d] adj. 有颜色的

单词thicker 原型：thick 形容词比较级 [thik][θ?k] adj. 厚的；浓密的；粗的

单词Iris ['ahy-ris]['a?r?s] n. 虹膜

解析虹膜是血管膜的最前部，呈环状。位于眼睛的晶状体的前方，将眼房分为前房和后房。

The pigment is melanin, same that makes our skin different colors.

译色素是黑色素，同样使我们的皮肤呈不同的颜色。

单词pigment ['pig-muhnt]['p?ɡm?nt] n. 色素； 颜料

单词melanin ['mel-uh-nin]['mel?n?n] n. 黑色素

单词skin [skin][sk?n] n. 皮肤；外皮

Now when the front layer is densely pigmented, it appears dark, like brown or even black (though shine a bright enough light and you'll see black eyes are just very dark brown).

译现在，当前一层是浓密的色素，它看起来很暗，像棕色，甚至黑色（尽管在足够亮的光线照射下，你会看到黑色的眼睛其实只是非常深的棕色）。

单词densely [dens][densli] adv. 密集地；浓厚地

单词shine [shahyn][?a?n] v. 照耀；发光；投光于

单词bright [brahyt][bra?t] adj. 明亮的；阳光的；生动的

If it's not pigmented, it appears light blue.

译如果没有着色，它就会呈现淡蓝色。

Why?

译为什么？

Same reason the sky's blue, light scatters in it.

译同样的原因，天空是蓝色的，光在其中散射。

单词sky [skahy][ska?] n. 天空

单词scatters 原型：scatter ['skat-er]['sk?t?] vt. 散播；撒 vi. 分散；消散

Light scattering is a different topic, but basically short wavelengths (ie blue) bounce differently in the fluffy front layer without pigment.

译光散射是一个另一个话题，但基本上短波长（即蓝色）在蓬松的前一层没有色素而反射的方式不同。

单词topic ['top-ik]['t?p?k] n. 题目；话题；标题

单词basically ['bey-sik-lee]['be?s?kli] adv. 基本上；主要地

单词wavelengths 原型：wavelength ['weyv-length]['we?vle?θ] n. 波长；波段

单词bounce [bouns][ba?ns] vi. 弹起

单词differently ['dif-er-uhnt-lee, 'dif-ruhnt‐]['d?fr?ntli] adv. 不同地

单词fluffy ['fluhf-ee]['fl?fi] adj. 毛绒绒的；蓬松的；空洞的

What about in between?

译中间呢？

Well it turns out if there's pigment but it's not super dense, it's a bit of a lighter brown or dark orange.

译如果有色素，但不是超浓的，会是浅棕色或深橙色。

单词super ['soo-per]['su?p?] adj. 超级的；极好的

单词dense [dens][dens] adj. 密集的；稠密的；浓密的

单词lighter ['lahy-ter]['la?t?] adj. light的形容词/副词比较级，更浅的

单词orange ['awr-inj, 'or-]['?r?nd?] adj. 橙色的

We call these amber eyes.

译我们称之为琥珀色的眼睛。

单词amber ['am-ber]['?mb?] adj. 琥珀的；琥珀色的

If it's between amber and blue, then it's like a cross between light orange and blue.

译如果它介于琥珀色和蓝色之间，那么它就像是浅橙色和蓝色之间的混合。

单词cross [kraws, kros][kr?s] n. 交叉

That's how you get green eyes.

译人就是这样有了绿色的眼睛的。

So that's how you get the spectrum: from blue to green to amber to brown to black.

译这就是光谱推进的方式：从蓝色到绿色到琥珀色到棕色到黑色。

单词spectrum ['spek-truhm]['spektr?m] n. 系列；幅度；范围；光谱

So what about "red" or "violet" eyes?

译那“红”色或“紫”色的眼睛呢？

单词violet ['vahy-uh-lit]['val?t] adj. 紫色的

Turns out I lied in the beginning; that back layer I mentioned that's always pigmented isn't in a medical condition: Albinism.

译哈哈，其实我一开始就说的不对；我提到的一直有色素沉着的那一层不是医学上的：白化病。

单词lied 原型：lie [lahy][la?] v. 说谎

单词beginning 原型：begin [bih-'gin][b?'ɡ?n] v. 开始

单词mentioned 原型：mention ['men-shuhn]['men?n] vt. 提到；说起

单词medical ['med-i-kuhl]['med?kl] adj. 医疗的；医学的；医药的

单词condition [kuh?n-'dish-uh?n][k?n'dn] n. 条件；情况

专有名词Albinism ['al-buh-niz-uhm]['?lb?n?z?m] n. 白化病；皮肤变白症

These folks unfortunately have a defect in producing melanin pigment, which is why they all have fair skin and light hair and such.

译不幸的是，这些人在产生黑色素方面有缺陷，这就是为什么他们都有浅白色的皮肤和浅色的头发等等。

单词folks 原型：folk [fohk][fk] n. 人们；（某类或来自某个地方的）人

单词unfortunately [uhn-'fawr-chuh-nit][?n'ftn?tli] adv. 不幸地；遗憾地

单词defect ['dee-fekt]['di?fekt] n. 缺点；缺陷

单词fair [fair][fe?] adj. （皮肤、毛发等）浅色的；白皙的

So why red?

译为什么会是红色呢？

It's the same reason you can get red eyes in flash photography; the red is the color of the retina in the back of the eye.

译同样的道理，你可以在闪光摄影中看到红色的眼睛；红色是眼睛后面视网膜的颜色。

单词flash [flash][fl] n. 闪光（灯）

单词photography [fuh-'tog-ruh-fee][f?'t?ɡr?fi] n. 摄影

单词retina ['ret-n-uh, 'ret-nuh]['ret?n?] n. 视网膜

Flash photography causes you to accidentally image peoples retinas.

译拍照时使用闪光灯会让你不小心拍到别人的视网膜。

单词accidentally [ak-si-'den-tl][ks?'dent?li] adv. 偶然地；意外地；附带地

单词image ['im-ij]['?m?d?] vt. 拍摄；描绘

Now without the pigment in the back layer of the iris, the iris almost functionally becomes like Saran Wrap; it's clear and doesn't block out light anymore.

译现在没有色素在虹膜的底层，虹膜的功能几乎变得像合成纤维包装；它是清晰的，不再遮光。

单词functionally ['fuhngk-shuh-nl]['fkn?li] adv. 功能上；机能上

单词block out v. 阻塞，阻断

单词anymore [en-ee-'mawr, -'mohr]['en?m] adv. (通常用于疑问句或否定句中，与not连用)再，也，还

专有名词Saran [suh-'ran][s?'r?n] n. [化]丝龙(一种合成纤维)

单词wrap [rap][r?p] n. 包装材料

So when you see red (or violet) eyes, you're seeing retina through their Iris.

译所以当你看到红色（或紫色）的眼睛时，你是通过虹膜看到视网膜的。

Side note: this is one reason why folks with albinism have poor vision.

译旁注：这是白化病患者视力差的原因之一。

单词vision ['vizh-uhn]['vn] n. 视力；视觉

The purpose of the iris is to act like a camera aperature.

译虹膜的作用就像照相机的光圈。

单词purpose ['pur-puhs]['pp?s] n. 目的；决心；意图

单词camera ['kam-er-uh, 'kam-ruh]['k?m?r?] n. 照相机；摄像机

Without pigment, it can't block out light like an aperature, removing a whole element of the focusing system of the eye.

译如果没有色素，它就无法像光圈一样阻挡光线，从而使眼睛的聚焦系统的完全失效。

单词removing 原型：remove [ri-'moov][r?'mu?v] v. 消除

单词element ['el-uh-muhnt]['el?m?nt] n. 要素；元素

单词focusing 原型：focus ['foh-kuhs]['fk?s] v. （使）集中；聚集；聚焦

Disclaimer: this is a bit of an oversimplification of how eye colors work, but it's fundamentally not too far off.

译免责声明：这是一个可能有些过于简单化的眼睛颜色的原理描述，但它基本与事实差距不大。

单词disclaimer [dis-'kley-mer][d?s'kle?m?] n. 放弃；弃权；免责声明

单词oversimplification [oh-ver-'sim-pluh-fahy][?vs?mpl?f?'ken] n. 过于简化

单词fundamentally [fuhn-duh-'men-tl-ee][?f?nd?'ment?li] adv. 从根本上；基本地

The genetics that go into eye color get very complex, don't think it's some single gene thing; I know this explanation makes it seem like there's just one toggle, but that's not how the genetic part of it works.

译关于眼睛颜色的基因很复杂，不要认为这是某个单一的基因引起的；我知道刚才这个解释使它看起来好像只有一个决定因素，但这不是基因部分如何起作用的全部。

短语part of ... （某事物的）一部分；例句：He received part of his education in England. 他有一部分教育是在英国接受的。

单词genetics 原型：genetic [juh-'net-ik][d'net?k] adj. 遗传的；基因的；起源的

单词complex [kuhm-'pleks]['k?mpleks] adj. 复杂的

单词gene [jeen][d?i?n] n. 基因

单词explanation [ek-spluh-'ney-shuhn][?ekspl?'nen] n. 解释；说明

单词toggle ['tog-uhl]['t?ɡl] n. 触发器；开关