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A clear-eyed look at computer vision syndrome

Recognize the symptoms and learn about ways to prevent it

In the dark about computer vision syndrome (CVS)? You're not alone. Even though the symptoms of CVS are more prevalent among computer users than repetitive strain injuries (RSI), most people haven't heard of it.

Fortunately, that's not a cause for concern, since doctors typically check for symptoms of CVS during routine eye exams. Symptoms include blurred vision or eyestrain; dry, itchy, red or burning eyes; and neck or back pain, among others. According to Dr. Robert Gross, chief of the Eye Service at MIT Medical, "If you have any of these symptoms and are more symptomatic when you're on the computer, then you have CVS."

The good news is that CVS doesn't cause long-term damage to your eyes, nor are there strict dos and don'ts to follow. That said, you can benefit from knowing what causes CVS and steps you can take to prevent or treat it.

According to Gross, if you are symptomatic, there are four things to consider:
  1. Do you have the right prescription for the distance between your eyes and the computer screen?
  2. Does your office setup — the placement of your chair, monitor and light source — minimize the likelihood of eyestrain?
  3. Are your eyes moist enough throughout the day?
  4. Do you work on a computer for long stretches of time or read difficult material on your display, such as articles from technical journals?
Here's the lowdown on each of these.

The Right Prescription

Getting the correct prescription for computer work depends on the distance between your eyes and the screen (see Your Office Setup below) and also depends on your age. The divider occurs around age 40 to 45, when presbyopia — the inability of the eye to focus sharply on nearby objects — becomes an issue. This age-related loss of focus stems from reduced elasticity in the crystalline lens behind the iris.

For a younger person who wears glasses or contact lenses and has CVS, an accurate prescription is usually all that's needed to correct the problem. Some in this group who are nearsighted find it more relaxing to use a second pair of glasses with a weaker prescription for work on the computer.

For older people, the solution is more complicated. Lined bifocals are usually inappropriate because the top half is for long distance and the bottom half, which would be the right strength for computer work, puts your neck in a bad posture. Progressive glasses may address this issue.

If you're over 50, though, even with progressive glasses you may still have to tilt your head to a degree that causes a stiff neck. If this is the case, you may want a dedicated pair of glasses that's optimal for the distance between your eyes and the computer.

Your Office Setup

The American Optometric Association provides guidelines for the angle and distance between your eyes and your monitor: "Optimally, the computer screen should be 15 to 20 degrees below eye level (about 4 or 5 inches) as measured from the center of the screen and 20 to 28 inches from the eyes."

You should also try to avoid glare or reflections on your screen. Position your screen and light sources to minimize these, using window shades or a desk lamp as needed. You can also adjust your screen brightness to a level you find comfortable. Gross doesn't recommend glare filters for computer screens unless you can't get rid of glare in any other way. In general, a glare filter's muting and loss of contrast makes reading more difficult.

While some find an anti-reflective coating on their glasses helpful, there's no scientific evidence that coatings or tints are effective.

Dry Eyes

Studies show that people blink less — a lot less — when they work at a computer. Blinking less leads to more evaporation, which can be especially problematic for people who wear soft contact lenses. A soft contact is essentially 50% water, so if there's a lot of evaporation, the lenses will often feel less comfortable as the day goes on. Gross suggests wearing glasses if you're uncomfortable when working long hours on the computer.

Your office environment may also be dry, contributing to eye discomfort. Using over-the-counter artificial tears can be very helpful. If you wear contact lenses, be sure to get drops that are approved for use with them.

Bottom line: blink more often, wear contact lenses judiciously, and use eye drops as needed.

Long Hours, Focused Reading

Close focus on work over long periods of time can strain your eyes. Gross also notes this interesting fact: If your reading material is difficult, your eyes will overfocus. "You'll get more tired reading a technical journal than the sports page, even if the font is exactly the same, at the same exact distance, for the same amount of time," he notes. Stress also produces more physical strain on the eyes, making them focus harder.

To remedy this type of eyestrain, Gross recommends the 20:20:20 rule: every 20 minutes take a 20-second break and look 20 feet away. The eye is at rest when it looks in the distance. "That's why people's eyes tend to get tired when they read, not so much when walking around," he says.

The game plan? Build in time to relax. Take a break and move around. Drink some water or other hydrating beverage. Change your focus: look out the window or across the room.


If you're experiencing symptoms of CVS, make an appointment with an eye care professional. Getting the right prescription for the eyewear you use at the computer relieves CVS symptoms more than any other measure. Community members can see optometrists in MIT Medical's Eye Service, while MIT Optical, in the Stratton Student Center, offers discounts on eyewear to MIT students and patients of the Eye Service.

You may also want to read up on CVS at the American Optometric Association or WebMD websites.

And remember to adopt the suggestions in this article: optimize your office setup, blink more, and observe the 20:20:20 rule. Your eyes deserve a break today — and every day.

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