Computer Vision Syndrome Affects Millions
Joanne Reitano is a professor of history at LaGuardia Community College in Long Island City, Queens. She writes wonderful books about the history of the city and state, and has recently been spending many hours — sometimes all day — at her computer to revise her first book, “The Restless City.” But while sitting in front of the screen, she told me, “I developed burning in my eyes that made it very difficult to work.”
乔安·雷塔诺(Joanne Reitano)是皇后区长岛市拉瓜地亚社区学院(LaGuardia Community College)的历史教授，著有若干关于长岛市和纽约州历史的佳作。近来她花了大量时间——有时是一整天——坐在电脑前，修改她的第一本书《不安之城》(The Restless City)。但她告诉我，坐在屏幕前的时候，“我眼睛里有灼烧感，很难好好工作。”
After resting her eyes for a while, the discomfort abates, but it quickly returns when she goes back to the computer. “If I was playing computer games, I’d turn off the computer, but I need it to work,” the frustrated professor said.
Dr. Reitano has a condition called computer vision syndrome. She is hardly alone. It can affect anyone who spends three or more hours a day in front of computer monitors, and the population at risk is potentially huge.
Worldwide, up to 70 million workers are at risk for computer vision syndrome, and those numbers are only likely to grow. In a report about the condition written by eye care specialists in Nigeria and Botswana and published in Medical Practice and Reviews, the authors detail an expanding list of professionals at risk — accountants, architects, bankers, engineers, flight controllers, graphic artists, journalists, academicians, secretaries and students — all of whom “cannot work without the help of computer.”
在全世界，可能患上电脑视觉综合症的人多达7000万，这一数字只会越来越大。尼日利亚和博茨瓦纳的眼部护理专家撰写了一篇关于该病症的报告，并发表在了《医疗实践与评论》(Medical Practice and Reviews)上。报告作者详细列出了可能会患上电脑视觉综合症的专业群体——会计师、建筑师、银行家、工程师、空管员、平面设计师、记者、学者、文秘和学生——这一名单正日益扩大，所有这些人“离开电脑的帮助就无法工作”。
And that’s not counting the millions of children and adolescents who spend many hours a day playing computer games.
Studies have indicated 70 percent to 90 percent of people who use computers extensively, whether for work or play, have one or more symptoms of computer vision syndrome. The effects of prolonged computer use are not just vision-related. Complaints include neurological symptoms like chronic headaches and musculoskeletal problems like neck and back pain.
The report’s authors, Tope Raymond Akinbinu of Nigeria and Y. J. Mashalla of Botswana, cited four studies demonstrating that use of a computer for even three hours a day is likely to result in eye symptoms, low back pain, tension headache and psychosocial stress.
前述报告的作者——尼日利亚的托普·雷蒙德·埃金比努(Tope Raymond Akinbinu)和博茨瓦纳的Y·J·马沙拉——引用的四项研究成果显示，即便每天使用电脑三小时，也有可能带来眼部症状、腰痛、紧张性头痛以及社会心理压力。
Still, the most common computer-related complaint involves the eyes, which can develop blurred or double vision as well as burning, itching, dryness and redness, all of which can interfere with work performance.
One reason the problem is so pervasive: Unlike words printed on a page that have sharply defined edges, electronic characters, which are made up of pixels, have blurred edges, making it more difficult for eyes to maintain focus. Unconsciously, the eyes repeatedly attempt to rest by shifting their focus to an area behind the screen, and this constant switch between screen and relaxation point creates eyestrain and fatigue.
Another unconscious effect is a greatly reduced frequency of blinking, which can result in dry, irritated eyes. Instead of a normal blink rate of 17 or more blinks a minute, while working on a computer the blink rate is often reduced to only about 12 to 15 blinks.
But there are additional problems. The head’s distance from the screen and position in relation to it are also important risk factors. To give the eyes a comfortable focusing distance, the screen should be about 20 to 26 inches away from the face. The closer the eyes are to the monitor, the harder they have to work to accommodate to it.
In addition, when looking straight ahead, the eyes should be at the level of the top of the monitor. The University of Pennsylvania’s ophthalmology department advises that the center of the monitor should be about four to eight inches lower than the eyes to minimize dryness and itching by lessening the exposed surface of the eyes because they are not opened wide. This distance also allows the neck to remain in a more relaxed position.
此外，当望向正前方的时候，眼睛应与显示器顶端平齐。宾夕法尼亚大学(The University of Pennsylvania)眼科学系建议，显示器中心应比眼睛低4至8英寸左右（约合10至20厘米），以尽量减少眼睛干涩和瘙痒的症状，因为这样的话就不用把眼睛睁得太大，眼球暴露在空气中的面积就会减少。
Yet, in a study in Iran of 642 pre-university students reported in Biotechnology and Health Sciences last year, 71 percent sat too close to the monitor for comfort, and two-thirds were improperly positioned directly opposite or below the monitor.
不过，伊朗的一项以642名高中生为对象的研究显示，71%的人坐得离显示器过近，好让自己更舒适一些；三分之二的人以不恰当的方式正对着显示器，或者坐得比显示器低。这项研究的结果于去年发表在了《生物技术与健康科学》(Biotechnology and Health Sciences)上。
Improper lighting and glare are another problem. Contrast is critical, best achieved with black writing on a white screen. The screen should be brighter than the ambient light — overly bright overhead light and streaming daylight force the eyes to strain to see what is on the screen. A bright monitor also causes your pupils to constrict, giving the eyes a greater range of focus.
You might need to reposition the desk, use a dimmer switch on overhead lights, or lower window shades to keep out sunlight. In addition, using a flat screen with an antiglare cover, and wearing glare-reducing or tinted lenses can help to minimize glare.
Be sure to use a font size best suited to your visual acuity, and have your eyes examined regularly — at least once a year — to be sure your prescription is up-to-date. This is especially important for people older than 40 and for children who are heavy users of computers because visual acuity can change with age. Make sure, too, that your monitor has a high-resolution display that provides sharper type and crisper images. And clean the monitor often with an antistatic dust cloth.
Those who work from printed materials, moving back and forth from them to the screen, could minimize neck strain by mounting documents on a stand next to the monitor. If, like me, you use many different printed documents at the same time, consider getting special computer glasses — bifocal or progressive lenses with the upper portion ideal for screen reading and the lower designed for print distance.
While prevention is most important, if you already have symptoms of computer vision syndrome, there are ways to reduce or eliminate them. Ophthalmologists suggest adhering to the “20-20-20” rule: Every 20 minutes, take a 20-second break and look at something 20 feet away.
Consciously blink as often as possible to keep eye surfaces well lubricated. To further counter dryness, redness and painful irritation, use lubricating eye drops several times a day. My ophthalmologist recommends products free of preservatives sold in single-use dispensers.
You can also reduce the risk of dry eyes by keeping air from blowing in your face and by using a humidifier to add moisture to the air in the room. And Dr. Reitano said her eye doctor also suggested applying warm moist compresses to her eyes every morning.