日本高清色视频在线视频在,国产香蕉97碰碰视频碰碰看,丰满少妇av无码区,精品无码专区在线,久久无码专区免费看,四虎欧美精品永久地址99,亚洲色无码一区二区三区

您現(xiàn)在的位置: Language Tips> Easy English> Odd Question  
 





 
眼睛顏色為什么會(huì)變?
[ 2007-08-08 08:27 ]

對(duì)很多人來(lái)說(shuō),眼睛的顏色從生下來(lái)那一天開(kāi)始就確定了,而且一輩子不變。但對(duì)另外一些人來(lái)說(shuō),卻不是這樣。究竟是什么原因會(huì)導(dǎo)致眼睛變色呢?

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 intriguing 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 fully matures in infancy and remains the same for life. But in a small percentage of adults, eye color can naturally become either noticeably darker or lighter with age.

What determines eye color is the pigment melanin. Eyes that have a lot of it in the connective tissue at the front of the iris, 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 permanently.

The first is a handful of ocular diseases like pigmentary 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 adolescence and adulthood, which occurred at nearly identical rates in identical twins.

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

pigment:色素
melanin: 黑色素
iris: 虹膜
stroma:基質(zhì)
ocular:眼睛的,視覺(jué)的
glaucoma: 青光眼
heterochromia: 異色癥
traumatic: 外傷的
hazel: 淡褐色

(來(lái)源;國(guó)際在線 英語(yǔ)點(diǎn)津 Annabel 編輯)

我想了解更多趣味百科知識(shí)

 
 
相關(guān)文章 Related Stories
 
         
 
 
 
 
 
         
 
 

48小時(shí)內(nèi)最熱門(mén)

     
  “好修的學(xué)分”怎么說(shuō)
  “拋媚眼”怎么說(shuō)
  Click《人生遙控器》(精講之九)
  布什又犯口誤 稱APEC為OPEC
  Dirty work:扮“白臉”

本頻道最新推薦

     
  為什么畢業(yè)時(shí)要穿學(xué)位服
  We cats can use chopsticks, too!
  不受歡迎的夜半歌聲:打鼾
  US Independence Day(美國(guó)國(guó)慶日)
  Exercise after dinner

論壇熱貼

     
   "電視選秀"怎么翻譯?
  how to translate "造星"
  how to translate "特供豬"?
  參加BBC在線競(jìng)賽 獲免費(fèi)倫敦游機(jī)會(huì)!
  how to say "代言"
  “試婚”怎么說(shuō)






<strong id="xdwva"><div id="xdwva"></div></strong>
<label id="xdwva"></label>

<thead id="xdwva"></thead>
    <label id="xdwva"></label>

  1. 日本高清色视频在线视频在,国产香蕉97碰碰视频碰碰看,丰满少妇av无码区,精品无码专区在线,久久无码专区免费看,四虎欧美精品永久地址99,亚洲色无码一区二区三区 久久九九久精品国产日韩经典 国产国语国拍精品 啊v在线观看高清无码 视频一区二区欧美 久久精品爱爱唉爱