8 . Our screens give out all kinds of light, especially blue light. Blue light, the argument goes, can affect your eye health, your sleeping patterns, and your health. Blue light glasses—technically they should be called “blue light blocking glasses”—filter out blue light, letting in the other wavelengths of light, thus theoretically reducing the danger that blue light presents. Blue light glasses are designed to reduce what’s known as digital eye strain (疲劳), or DES. There are many symptoms associated with DES, including headaches, dry eyes, and unclear vision.
How effective are blue light glasses? We’ll start with the bad news: there is no evidence that blue light glasses have any effect on eye strain from digital screens. In fact, one British glasses dealer was actually fined for indicating that blue light glasses can protect against DES, given that there’s no scientific evidence of this. What’s more likely is that DES is caused by overuse, or misuse of eyes. After all, the sun is a substantially more powerful provider of blue light than our screens, and it has been decidedly proved that DES isn’t associated with the sun at all. The general agreement is that DES is caused by spending too long, staring too hard, and sitting too close to our screens. Health experts generally recommend taking breaks to prevent DES, rather than relying on blue light glasses.
But there is one thing that blue light glasses might help with. Some studies have indicated that blue light can be bad for our circadian rhythms (生理节奏). In other words, exposure to blue light could make it harder to fall asleep. There haven’t been enough studies to tell if blue light glasses, worn for a few hours before bed, could help you sleep better, but it’s not out of the question.
That said, there are interesting reports of people loving their blue light glasses. Even if it’s just the placebo (安慰剂) effect, well, that can be incredibly powerful, and if it works on you, keep doing it.
1. What does the underlined part “filter out” in paragraph 1 mean?
| A．Appear or happen gradually. | B．Remove something particular. |
| C．Bring something into existence. | D．Tell something apart from others. |
2. What is DES likely caused by?
| A．The blinding sun light. | B．Unfit and cheap glasses. |
| C．Improper use of eyes. | D．All kinds of natural blue light. |
3. What does paragraph 3 mainly tell us about blue light glasses?
| A．They may be good for sleep. | B．They can excite people. |
| C．They can help with nothing. | D．They are bad for circadian rhythms. |
4. What is the author’s attitude to blue light glasses?
| A．Intolerant. | B．Optimistic. |
| C．Objective. | D．Conservative. |
