We know that the blue light emitting from our smartphones isn’t good for our eyes, but a new study has discovered just how much damage it can cause. Researchers say that this light is absorbed by vital molecules in our retina and triggers the production of a toxic chemical that kill cells.

This damage can lead to large blind spots in our vision that are the hallmark of macular degeneration, a disease that leads to blindness.

The team from the University of Toledo in Ohio says it is urging the public not to use phones in the dark because this can dilate pupils and lead to even more harmful blue light entering our eyes.

Age-related macular degeneration (AMD) is the leading cause of vision loss for those aged 50 or older, according to the U.S. National Eye Institute.

The condition occurs when the macula, an oval area near the center of the retina that allows for sharp vision, becomes damaged.

Sufferers will experience blurred vision or even “blind spots” in their central vision that may grow larger as the retina dies.

For this study, the team decided to focus on retinal, a form of vitamin A found in the retina that coverts light into metabolic energy.

Photoreceptor cells, known more commonly as rods and cones, use retinal to covert light into signals that are sent to the brain.

“The human eye reflects UV light (such as from the sun) very well but it allows blue light to enter and the retinal can absorb blue light very well,” said lead author Ajith Karunarathne, an assistant professor in the UT department of chemistry and biochemistry.

Karunarathne noted that blue light alone or retinal that hadn’t absorbed blue light did not have any effect on the cells.

He added that there was no activity when retinal was exposed to other light colors such as green, red or yellow.

The team did find a molecule, a vitamin E derivative known as alpha tocopherol, that can stop the cells from dying.

“When you damage the photoreceptor cells, they’re damaged for good, so the vitamin E derivative currently just mitigates damage,” said Karunarathne.

Words to Learn 相关词汇

【变性】biànxìng degeneration deterioration of a tissue or an organ in which its function is diminished or its structure is impaired

【扩大】kuòdà dilate become wide

我们都知道智能手机发出的蓝光对眼睛有伤害，但一项最新研究解释了蓝光能造成的伤害程度。

研究人员称，视网膜上面一些重要的分子会吸收这些蓝光，并会产生能杀死细胞的有毒化学物质。

这种伤害可导致视力出现较大的盲点，这也是黄斑变性的典型特征。黄斑变性会导致失明。

俄亥俄州托莱多大学的研究小组呼吁公众不要在暗处使用手机，因为这会使瞳孔放大，导致更多的有害蓝光进入眼睛。

美国国家眼科研究所的数据显示，老年性黄斑变性是50岁及以上人群视力丧失的主因。

当视网膜中心附近椭圆形的黄斑区受到损害时，就会出现视力丧失。黄斑区的状况决定视力水平。

黄斑变性患者通常会觉得中心视觉区域视力模糊，甚至出现“盲点”，而且随着视网膜细胞坏死，视觉模糊和出现盲点的区域会扩大。

在此次研究中，研究小组把重心放在视黄酮上，这是视网膜上发现的一种维生素A，能够把光转换成能量代谢。

感光细胞（通常被称为干体与锥体细胞）通过视黄酮将光线转换为信号，并传递给大脑。

研究报告的主要作者卡如那拉西恩博士说：“人的眼睛反射紫外光（比如来自太阳）的能力很强，但会让蓝光进入眼睛，视黄酮吸收蓝光的能力也很强。”他是托莱多大学化学和生物化学系的助理教授。

卡如那拉西恩博士指出，仅仅是蓝光，或是没有吸收蓝光的视黄酮不会对感光细胞有任何影响。

他补充说，当视黄酮暴露于绿色、红色或者黄色等浅色时，不会有任何反应。

研究小组发现了一种分子能够阻止细胞的死亡，这是一种维生素E的衍生物，也称为α生育酚。

卡如那拉西恩博士说：“感光细胞受到的伤害不可逆，所以维生素E的衍生物目前也只能减轻这种伤害。” (Chinadaily.com.cn)