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人的眼睛颜色可随年龄变化
添加时间:2014-06-30 16:14:35 浏览次数: 作者:未知
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  • The facts It can bend light, bring the world into focus, and next to the human brain may be our most complicated organ. But for many people the most intriguing1 feature of the human eye is simply its color.

    Can it really change for no apparent reason?

    In most people, the answer is no. Eye color fully2 matures in infancy3 and remains4 the same for life. But in a small percentage of adults, eye color can naturally become either noticeably darker or lighter5 with age.

    What determines eye color is the pigment6 melanin. Eyes that have a lot of it in the connective tissue at the front of the iris7, called the stroma, are darker, while those that have less tend to be lighter.

    The levels of melanin generally remain the same throughout life, but a few things can change them permanently8.

    The first is a handful of ocular diseases like pigmentary9 glaucoma. Another is a condition called heterochromia, or multicolored eyes, which affects about 1 percent of the population and is often caused by traumatic injuries. An example of this can be seen in the rock star David Bowie, who attributes his contrasting eye colors, hazel and light blue, to a blow to the face as a child.

    The third cause appears to be genetics. A study in 1997, for example, looked at thousands of twins and found that 10 percent to 15 percent of the subjects had gradual changes in eye color throughout adolescence10 and adulthood11, which occurred at nearly identical rates in identical twins.

    The bottom lines Eyes can change color in some people because of genetics or injury.

    眼睛颜色是人体最重要的特征,但科学家日前表示,人眼颜色可以改变。

    据《纽约时报》日前报道,通常情况下,人眼在外伤作用下可能会改变颜色,但若没有外伤的作用,眼睛颜色还会自动改变吗?对大部分人而言,答案是否定的。眼睛颜色在人幼年时期已经形成,且基本上终生不变。但是,一小部分成年人眼睛的颜色却可以随着年龄的增长明显地变深或者变浅。

    科学家指出,决定人眼颜色的是眼球虹膜前部的基质中的黑色素,黑色素含量越多,人眼的颜色就越深,反之越浅。而基质中的黑色素含量在通常情况下是终生保持不变的,除非某些异常情况发生导致它发生永久性的改变。

    首先,改变眼部黑色素的是眼部疾病,如青光眼(患者瞳孔内出现青绿色的反光)。

    其次,是由外伤引起的彩色眼(又名双眼异色症),主要表现为双眼颜色出现差异,如英国著名的摇滚乐手大卫·鲍伊,他的一只眼睛为浅蓝色,而另一只为棕色。据悉,鲍伊曾在幼年时期因脸部受伤而导致眼睛变色。

    第3种改变眼睛颜色的原因是遗传基因。科学家在1997年对数千对双胞胎研究后发现,10%至15%的双胞胎同时在青春期和成年后眼睛颜色会逐渐改变,这证明,有相似基因的双胞胎发生眼睛变色的几率也是相同的。

    科学家最后明确指出,导致人眼睛颜色变化的的关键就是遗传基因和外伤。

     12级    英文科普 


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    1 intriguing [ɪnˈtri:gɪŋ] vqyzM1   第7级
    adj.有趣的;迷人的v.搞阴谋诡计(intrigue的现在分词);激起…的好奇心
    参考例句:
    • These discoveries raise intriguing questions. 这些发现带来了非常有趣的问题。
    • It all sounds very intriguing. 这些听起来都很有趣。 来自《简明英汉词典》
    2 fully [ˈfʊli] Gfuzd   第9级
    adv.完全地,全部地,彻底地;充分地
    参考例句:
    • The doctor asked me to breathe in, then to breathe out fully. 医生让我先吸气,然后全部呼出。
    • They soon became fully integrated into the local community. 他们很快就完全融入了当地人的圈子。
    3 infancy [ˈɪnfənsi] F4Ey0   第9级
    n.婴儿期;幼年期;初期
    参考例句:
    • He came to England in his infancy. 他幼年时期来到英国。
    • Their research is only in its infancy. 他们的研究处于初级阶段。
    4 remains [rɪˈmeɪnz] 1kMzTy   第7级
    n.剩余物,残留物;遗体,遗迹
    参考例句:
    • He ate the remains of food hungrily. 他狼吞虎咽地吃剩余的食物。
    • The remains of the meal were fed to the dog. 残羹剩饭喂狗了。
    5 lighter [ˈlaɪtə(r)] 5pPzPR   第8级
    n.打火机,点火器;驳船;v.用驳船运送;light的比较级
    参考例句:
    • The portrait was touched up so as to make it lighter. 这张画经过润色,色调明朗了一些。
    • The lighter works off the car battery. 引燃器利用汽车蓄电池打火。
    6 pigment [ˈpɪgmənt] gi0yg   第8级
    n.天然色素,干粉颜料
    参考例句:
    • The Romans used natural pigments on their fabrics and walls. 古罗马人在织物和墙壁上使用天然颜料。
    • Who thought he might know what the skin pigment phenomenon meant. 他自认为可能知道皮肤色素出现这种现象到底是怎么回事。
    7 iris [ˈaɪrɪs] Ekly8   第12级
    n.虹膜,彩虹
    参考例句:
    • The opening of the iris is called the pupil. 虹膜的开口处叫做瞳孔。
    • This incredible human eye, complete with retina and iris, can be found in the Maldives. 又是在马尔代夫,有这样一只难以置信的眼睛,连视网膜和虹膜都刻画齐全了。
    8 permanently ['pɜ:mənəntlɪ] KluzuU   第8级
    adv.永恒地,永久地,固定不变地
    参考例句:
    • The accident left him permanently scarred. 那次事故给他留下了永久的伤疤。
    • The ship is now permanently moored on the Thames in London. 该船现在永久地停泊在伦敦泰晤士河边。
    9 pigmentary [pɪɡ'mentrɪ] 066ccc8cbf56de8a896a1f3d6ce38ce2   第8级
    adj.颜料的,色素的
    参考例句:
    • The first is a handful of ocular diseases like pigmentary glaucoma. 首先,改变眼部黑色素的是眼部疾病,如青光眼(患者瞳孔内出现青绿色的反光)。 来自互联网
    10 adolescence [ˌædəˈlesns] CyXzY   第8级
    n.青春期,青少年
    参考例句:
    • Adolescence is the process of going from childhood to maturity. 青春期是从少年到成年的过渡期。
    • The film is about the trials and tribulations of adolescence. 这部电影讲述了青春期的麻烦和苦恼。
    11 adulthood [ˈædʌlthʊd] vKsyr   第8级
    n.成年,成人期
    参考例句:
    • Some infantile actions survive into adulthood. 某些婴儿期的行为一直保持到成年期。
    • Few people nowadays are able to maintain friendships into adulthood. 如今很少有人能将友谊维持到成年。

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