居家办公伤眼睛吗？

文/伊索贝尔·惠特科姆 译/俞月圆

从尽情刷网飞剧集到开Zoom 会议，新冠疫情显著增加了我们日常生活中盯着屏幕的时间。花在电子设备上的时间可能会对眼睛造成负担。所以，自从开始远程办公以来，你可能更频繁地感到头痛、眼睛累或视力模糊，并非只有你如此。这些都是数字视疲劳（也被称为“计算机视觉综合征”）的症状。

2先说一条好消息：尽管名叫视疲劳，但它并非物理性损伤，也没有对眼睛造成长期伤害的风险。尽管如此，视疲劳也不是闹着玩的，它可能会让数字时代的生活变得困难。好在采取一些简单的步骤，就可以预防或消除这些症状。

数字视疲劳的原因

3费城儿童医院的眼科医生普里扬卡·库马尔说，不看屏幕的时候，人大约每四秒眨一次眼。每次眨眼都会新挤出一层眼泪，而这眼泪是油脂、水分和黏液的混合物，可以润滑和保护眼球。库马尔说，使用屏幕时，我们眨眼的次数会减少一半左右。这会导致我们的眼睛产生干涩感或沙砾感，甚至可能有刺痛感、灼烧感，或涌出泪水。这时的泪水不同于平常眨眼时分泌的泪水，是在大脑意识到眼睛太干时产生的。这种泪水的成分主要是水，所以往往很快就会蒸发。库马尔说：“流泪其实暗示了眼睛干涩。”

4头痛和视力模糊有时与数字视疲劳相关，但它们的产生有另外的根本原因。花好几个小时看屏幕会导致负责协调双眼的肌肉感到疲劳，因为眼肌需要长时间不断地将我们的视线集中在相同的距离上。亚拉巴马大学视光学院教授凯瑟琳·魏泽说：“这就像一整天都在跑马拉松。”她还说，如果看屏幕的时间足够长，任何人都会出现这一系列特殊症状，但眼部协调方面有潜在问题的人尤其容易受影响。因此，如果你感到头痛和视力模糊，如果你发现遮住一只眼睛之后更容易将视线聚焦在屏幕上，那最好去检查一下眼睛，看看是否确实存在潜在的眼部协调问题，魏泽如是说。

看屏幕太久会伤眼

5对于成年人来说，视疲劳可能会带来痛苦和不便，但不会对眼睛造成实际损害。然而，库马尔说，对于八岁以下的儿童来说，情况就不同了。这是因为他们的眼肌还没有发育完全。有证据显示，长时间看屏幕会导致近视。一些研究表明，在新冠疫情期间，近视在儿童中变得更加常见，这可能是因为他们花了大量时间进行线上学习。美国医学会专科杂志《眼科学纪要》刊载的一项研究发现，近视患病率提高了三倍之多。通常情况下，近视可以通过配眼镜或隐形眼镜来矫正。但在极端情况下，近视可能导致视网膜脱落，这种损伤通常会导致失明。

预防视疲劳

6幸运的是，保护眼睛免受屏幕使用时间的影响并不难，而且相关措施可以和你的日常生活无缝融合。库马尔说，最重要的一步是休息。她提倡20—20—20—2 法则：每隔20分钟，盯着20 英尺外的东西至少20 秒，并尝试一天花两个小时待在户外。

7将电脑显示器放在合适的位置也很重要。库马尔说，应该把屏幕放置在离眼睛大约两英尺的地方，比你不用倾斜头部时视线自然停留的地方高几英寸。如果比这个距离更近，你的眼睛就得付出额外的努力。

8库马尔说，如果你已经感觉到眼干或者眼睛有灼烧感，人工泪液可能会有所帮助。如果你戴的是隐形眼镜，至少在你工作的时候试着换成普通眼镜。隐形眼镜实际上会加重干眼症状。

9最后，魏泽说还应该避开眩光。眩光不是沿着一条清晰路径直射视网膜的中心，而是在眼睛周围来回弹跳，使眼睛难以聚焦。这使得眼睛内部的肌肉（比如负责扩张瞳孔的肌肉）过度疲劳。要确保环境光线与来自屏幕的光线相似，好让你的眼睛避开眩光。要减少在户外的工作，关闭明亮的顶灯，还要避免在昏暗的条件下工作。魏泽补充说，带有防反射涂层的眼镜也有助于减少受眩光刺激。

10采取这些措施后，不要指望立竿见影。匹兹堡大学医学院眼科教授斯科特·德雷克斯勒说，如果你已经感受到视疲劳的影响，可能需要过一段时间才能恢复正常。所幸你不需要完全远离屏幕。从视疲劳中恢复的方法和预防的方法差不多。几天后你应该就会感觉好多了。

防蓝光眼镜值得入手吗？

11有关蓝光的负面影响已经有很多宣传了。一些验光师和配镜师声称蓝光会损害视网膜，可能导致长期的视力问题。这些说法有一些研究结果作依据，但美国眼科学会以证据不足为由，不建议使用防蓝光镜片。

12毫无疑问，部分蓝光是有害的，例如来自太阳的紫外线会导致黄斑变性和癌症，但并不是所有的蓝光都同样有害。魏泽说，我们的电子设备不会产生紫外线，而且我们使用这些设备时接触到的蓝光总量其实相当少。她补充说，如果你担心眼睛的长期健康，那么比起在电脑前工作时佩戴防蓝光眼镜，买一副高质量的防紫外线（UVA/UVB）太阳镜在你长时间暴露在阳光下时佩戴，这样更有用。 □

From Netflix binges to Zoom meetings, the coronavirus pandemic significantly increased the amount of screen time in our daily lives. All that time on devices can be taxing on the eyes—so if you’ve experienced more headaches, eye fatigue, or blurred1blurred 模糊不清的。vision, since remote work began, you’re not alone. These are symptoms of digital eye strain, also known as “computer vision syndrome”.

2Here’s the good news first: Despite its name, eye strain isn’t a physical injury and doesn’t carry any risk of longterm damage to the eyes. Still, it’s no fun, and can make life difficult in the digital age. Fortunately, there are simple steps you can take to prevent, or recover from, these symptoms.

What causes digital eye strain?

3When we’re not looking at screens,humans blink about once every four,says Priyanka Kumar, an ophthalmologist at the Children’s Hospital of Philadelphia. Each blink squeezes out a layer of fresh tears, a mixture of oil, water,and mucus that lubricates and protects the eye. When we use screens, we blink about half that much, Kumar says. This can cause our eyes to feel dry or gritty.They might even sting, burn, or tear up.These tears are different from the ones our eyes would normally produce when blinking—they’re made when our brain realizes our eyes are too dry and because they’re mostly water, they tend to evaporate quickly. “Tearing is actually a nudge that the eyes are dry,” Kumar says.

4The headaches and blurred vision sometimes associated with digital eye strain have a different root cause.Spending hours on screens can cause the muscles that coordinate our eyes to tire from the constant motion of focusing our sight on the same distance for a long period of time. “It’s like running marathons all day long,” says Katherine Weise, a professor at the University of Alabama school of Optometry. Enough screen time can cause anyone to develop this particular set of symptoms,but people who have an underlying issue with eye coordination are especially vulnerable, Weise says. So if headaches and blurred vision are your problem,if you find it easier to focus on your screen when you cover one eye, it’s probably a good idea to get your eyes checked out, in case you do have an underlying problem with eye coordination,Weise says.

When screen time causes harm

5For adults, eye strain can be painful and inconvenient, but it doesn’t cause actual damage to the eye. For children younger than eight-years old, though,it’s a different story, Kumar says. That’s because their eye muscles haven’t fully developed. There’s some evidence to suggest that lots of screen time can contribute to nearsightedness. Some studies suggest that nearsightedness has become more common in children during the COVID-19 pandemic, likely due to all that time spent learning virtually. One study, published inJAMA Ophthalmology, found that the increase was as much as three-fold. Usually, this condition is treatable with a prescription for glasses or contact lenses. But in extreme cases, nearsightedness can lead to retinal detachment, an injury that often results in blindness.

Preventing eye strain

6Luckily, protecting the eyes from screen time isn’t hard and can seamlessly fit into your daily routine. The most important step is to take breaks,Kumar says. She encourages the 20-20-20-2 rule: Every 20 minutes, look at something 20 feet away for at least 20 seconds, and try to spend two hours of the day outside.

7Placing your monitor in the proper location is also key. Set up your screen roughly two feet from your eyes and a few inches above where your sight naturally rests without tilting your head,Kumar says. Any closer, and your eyes will work harder than they need to.

8If you’re experiencing dryness or burning, artificial tears might help, Kumar says. And if you use contact lenses,try switching to glasses, at least while you’re working—contact lenses can actually exacerbate2exacerbate 使恶化，使加剧。dry-eye.

9Finally, avoid glare, Weise says.Rather than shining in a clear path straight to the center of our retina, glare pinballs around our eye, making it difficult for our eyes to focus. That overworks the muscles inside our eye, such as those that dilate the pupils. Give your eyes a break from glare by making sure that your ambient light is similar to the light coming from your screen—limit the work you do outside and switch off bright overhead lights, but also avoid working in low-light conditions. Glasses with anti-reflective coating can also help limit your exposure to glare, Weise adds.

10Once you’ve begun implementing these strategies, don’t expect instant relief. If you’re already feeling the effects of eye strain, it could take some time to feel back to normal, says Scott Drexler, a professor of ophthalmology at the University of Pittsburgh School of Medicine. Fortunately, you don’t need to take a complete hiatus from screen time. Recovery from eye strain looks similar to prevention. You should start to feel better in a few days.

Are blue-light filtering lenses worth the investment?

11Much has been made about the negative effects of blue-light. Some optometrists and opticians claim that blue-light damages the retina, which can lead to long-term vision problems. These claims are based on a few studies, but the American Academy of Ophthalmology doesn’t recommend the use of blue-light filtering lenses, citing insufficient evidence.

12Without a doubt, some blue light is damaging. Take, for instance, the ultraviolet rays from the sun, which can cause macular degeneration and cancer. But not all blue-light is equally harmful. Our devices don’t produce ultraviolet light,and the total amount of blue-light they do expose us to is actually fairly minimal,Weise says. If you’re concerned about your long-term eye health, a high-quality pair of UVA/UVB3UVA/UVB 长波紫外线/中波紫外线，穿透力较强，大量照射会对人体造成伤害。-filtering sunglasses to wear when you spend long periods of time in the sun, is a much better investment than blue-light filtering lenses for computer work, she adds. ■