Blue light is a type of electromagnetic radiation with a very short wavelength that produces a high amount of energy. While it’s true that light can damage your eyes under certain circumstances, there’s no scientific evidence suggesting that blue light is harmful to our eyes. But many people still think it is, which is why blue light-blocking glasses are so popular.

“Everyone is very concerned that (blue light) may be causing damage to the eye, and it’s a valid concern, but there’s no evidence it may be causing any irreversible damage,” Dr. Rahul Khurana, clinical spokesman for the American Academy of Ophthalmologists, told Business Insider.

Blue light exposure is nothing new. In fact, the sun is the largest source of blue light. Moreover, blue light is also present in fluorescent and LED light.

But if blue light isn’t harmful, then why are we constantly rubbing our peepers when we’re looking at our screens? The answer is eyestrain. More than 60 percent of people experience problems associated with digital eyestrain. And blue light, it seems, isn’t the cause. Instead, our eyes are so strained because most of us blink less when we stare at our digital devices.

So if eyestrain is the real issue, blue light-blocking glasses are probably useless. However, wearing them could potentially help you get a good night’s sleep. That’s because blue light, research has shown, affects your body’s circadian rhythm, your natural wake and sleep cycle. According to Harvard researchers, any kind of light — including blue light — can tamp down your body’s ability to secrete melatonin, a hormone that helps you sleep.

Here are some tips on protecting your eyes:

Position your screen 20-30 inches away from your face, and make sure your eyes are level with the very top of your monitor. The key thing to remember is that you should be looking slightly down at your work. The center of the screen should be located between 15 and 20 degrees below horizontal eye level. Follow the 20-20-20 rule. Look away from your screen every 20 minutes for 20 seconds at a time and focus on a fixed point 20 feet away.

Words to Learn 相关词汇

【不可逆的】bùkěnì de irreversible impossible to reverse

【眼疲劳】yǎn píláo eyestrain fatigue or irritation of the eyes, resulting from excessive use

蓝光是一种波长非常短、能量巨大的电磁辐射。虽然在某些情况下光线确实会损伤我们的眼睛，但是目前并没有科学证据表明蓝光对我们的眼睛有害。不过许多人仍然认为蓝光确实有害，这就是防蓝光眼镜如此受欢迎的原因。

美国眼科学会临床发言人拉胡尔•库拉纳博士对商业内幕网表示：“每个人都非常担心蓝光可能会对眼睛造成损害，这种担忧是合理的，但是目前还没有证据表明蓝光可能会对眼睛造成任何不可逆转的损伤”。

蓝光照射并不罕见。事实上，太阳就是蓝光最大的来源。此外，蓝光也存在于荧光灯和LED灯中。

但如果蓝光是无害的，为什么我们在看屏幕的时候会不停揉眼睛呢？

真正的答案是眼睛疲劳：超过60%的人存在因使用电子产品导致的眼疲劳问题。而蓝光似乎并不是造成这些问题的原因。我们的眼睛之所以会如此疲惫，是因为大多数人在盯着电子产品时，眨眼的次数会减少。

也就是说，如果眼疲劳才是真正的问题，那么防蓝光眼镜可能是无用的。

不过，戴上它也许可以帮你改善睡眠。因为研究表明，蓝光会影响人体的昼夜节律，即生物钟。

据哈佛大学的研究人员称，任何一种光（包括蓝光）都会降低人体分泌褪黑素的能力，而褪黑素正是一种帮助你入眠的激素。

以下是几条何保护双眼的小贴士：

将屏幕放在距离脸部20-30英寸（50-70厘米）的位置，确保你的眼睛与屏幕顶部齐平。记住，关键是当你看屏幕时视线应该是稍微向下倾斜的。屏幕中心应该位于水平视线以下15到20度之间。

遵循20-20-20法则。每隔20分钟将视线从屏幕前移开，盯着20英尺（约6米）外的一个固定点看20秒。

(Chinadaily.com.cn)