對很多人來說，眼睛的顏色從生下來那一天開始就確定了，而且一輩子不變。但對另外一些人來說，卻不是這樣。究竟是什么原因會導(dǎo)致眼睛變色呢？
y':JU wUN pNFVa<D 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.
\wR;N/tg oaac.7.fV Can it really change for no apparent reason?
w;b;rHAZ\ 62.)fCQ^ 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.
hQb3 8W[ ,gO(zI-1 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.
;9MIapfUd( ee2k..Tq# The levels of melanin generally remain the same throughout life, but a few things can change them permanently.
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