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Scientists have discovered strands of genetic code linked to short sight, the most common eye disorder in the world.
The findings shed light on what goes awry to make distant objects look blurred, and raises the prospect of developing drugs to prevent the condition.
Understanding the biological glitches behind short-sightedness could help researchers develop eye drops or tablets that could be given to children to stop their vision from failing as they get older.
Short-sightedness, or myopia, usually starts to manifest early on in life.
The extent to which genes are to blame varies, but for those with the worst vision, around 80% of the condition is caused by genetic factors.
Two separate studies, published in Nature Genetics journal, found variations in DNA that were more common in people with short sight. Chris Hammond, at King's College, London, found one section of DNA on chromosome15 was more common in people with myopia. Caroline Klaver, at Erasmus Medical Centre in Rotterdam, found another strand, also on chromosome 15, linked to short sight.
The variations in DNA amount tomisspellings in the genetic code. These alter the activity of three genes that control the growth of the eyeball and ensure light entering the eye is converted into electrical pulses in the retina.
The discovery helps scientists piece together how a healthy eye becomes short-sighted and points the way to medicines to prevent it in children.
"My hope is that we can identify a pathway that we can block with eyedrops or tablets that will stop the eye growing too much and without interfering with normal brain development or other processes in the body," Hammond told the Guardian.
Some eye conditions are already being treated by replacing the faulty genes that cause them, but Hammond and Klaver said that too many genes contribute to short sight to make it a realistic option.
參考譯文：
科學家最近發現了一組與近視有關的遺傳密碼。近視是目前世界上最常見的眼部疾患。
這項發現有助于闡明近視的成因，并為研發預防近視的藥物帶來了希望。
找到近視的生物起因可以幫助研究人員研制出防止兒童視力隨年齡增長不斷下滑的眼藥水或藥劑。
近視往往形成于青少年時期。
對不同的近視患者來說，基因的致病因素所占比例不同，但對于視力極差的群體而言，大約80%的病例都是基因導致的。
發表在《自然-遺傳學》期刊上的兩項獨立研究都發現了更常見于近視患者的DNA改變。倫敦大學國王學院的克里斯.哈蒙德發現，15號染色體上的一個DNA片段更常見于近視患者。鹿特丹伊拉斯莫丹醫學中心的卡羅琳.克拉弗發現，15號染色體上的另一段DNA與近視有關。
這項發現幫助科學家完整理解了健康的眼睛如何患上近視，并為研制兒童時期預防近視的藥物指明了方向。
DNA變化相當于“拼錯”了遺傳密碼，改變了三種基因的活動。這三種基因控制眼球生長、確保眼部所見光線在視網膜轉化為電脈沖。
哈蒙德在接受衛報采訪時說：“我希望我們可以找到預防近視的眼藥水或藥劑，防止眼部發育過快，同時不打亂正常的腦部發育或其它身體活動。”
一些眼病患者已通過替換那些錯誤基因接受治療，但哈蒙德和克拉弗表示，較大的挑戰是跟近視相關的基因很多。
