chemical found in the drink prevents deteriorating¹ eyesight and possible blindness from retinal degeneration due to glaucoma, ageing and diabetes².

Researchers at Cornell Univesity in New York were looking at coffee's antioxidant effects when they made the discovery.

Coffee contains 1 percent caffeine but between 7 and 9 percent chlorogenic acid which is a strong antioxidant.

The study, published in the Journal of Agricultural and Food Chemistry, found that in mice this acid prevented retinal degeneration.

Chang Y. Lee, a professor of food science and the study's senior author said: ‘The retina is a thin tissue layer on the inside, back wall of the eye with millions of light-sensitive cells and other nerve cells that receive and organise³ visual information.

‘It is also one of the most metabolically⁴ active tissues, demanding high levels of oxygen and making it prone⁵ to oxidative stress.

‘The lack of oxygen and production of free radicals⁶ leads to tissue damage and loss of sight.’

He added: ‘The study is important in understanding functional⁷ foods, that is, natural foods that provide beneficial health effects.

‘Coffee is the most popular drink in the world, and we are understanding what benefit we can get from that.’

Previous studies have shown that coffee also cuts the risk of such chronic⁸ diseases as Parkinson's, prostate cancer, diabetes, Alzheimer's and age-related cognitive⁹ declines.

研究发现，咖啡中的一种化学成分可防止视力下降，甚至可预防青光眼、角膜老化及糖尿病所引起的视网膜退化，从而防止失明。

这项研究是纽约康奈尔大学的研究者们在研究咖啡的抗氧化作用时意外发现的。咖啡中包含1%的咖啡因，但是有7%至9%的强抗氧化剂绿原酸。这项发表在《农业与食品化学期刊》的研究发现，小白鼠体内的绿原酸可以防止视网膜退化。

食品科学教授、该研究作者之一李昌说道：“视网膜是眼中一层薄薄的膜状组织，是眼睛数以万计的感光细胞和其他神经细胞的接收和组织视觉信息的后壁。它也是新陈代谢最活跃的组织之一，因此需要很高的含氧量去应对氧化压力。缺少含氧量和自由基的产生能导致视网膜组织损坏和失明。”

他还说道：“这项研究对于了解食物的功能十分重要。也就是说天然食品对我们的健康有益。”

“咖啡是世界上最受欢迎的饮品。我们现在知道了我们可以从中收获什么样的好处。”

在此之前，曾有研究表明咖啡还可以降低帕金森氏症、前列腺癌、糖尿病、老年痴呆症以及其他由于年老引起的认知衰退等慢性疾病的风险。