Recognizing and Treating Computer Vision Syndrome
Recognizing and Treating Computer Vision Syndrome
Specialty lenses can help treat subtle vision problems that affect many people who use computers every day.
By Larry K. Wan, OD, San Jose, Calif.
At my practice in Silicon Valley, with Ebay and Apple just across the street, we see many intensive computer users. But patients don't have to work in information technology to spend hours in front of their computers. We all do it. Our patients do it, too.
That's why it's important to determine if our patients have computer vision syndrome (CVS), one of the most common focusing fatigue problems that affect most people who use a computer for at least several hours a day. With a few questions and some simple tests, we can recommend specialty computer lenses and make all those hours in cyberspace more comfortable for patients.
Cause and Prevalence
Printed text and images have a very high resolution. The black ink on a magazine page is very black, contrasting against a densely white background. The letters appear to have very crisp edges. Thus, our eyes focus easily on the page.
Text on a computer screen, on the other hand, has a much lower resolution. Characters are made up of tiny dots of light, or pixels, which make edges irregular. Even the individual pixels aren't uniform; they have bright centers that dim toward the edges. Our eyes constantly accommodate to stay focused. They continually cycle between the resting point of accommodation and focusing on the screen, an effort that leads to muscle fatigue and eyestrain, or CVS. What's more, the eyeglasses that help people with reading or distance vision don't help them focus on a computer screen located in the intermediate range, about 20 to 26 inches from their eyes.
The American Optometric Association estimates that 70 to 75 percent of computer workers have eye and vision problems.1 That means people who work on computers or spend hours using home computers each day are at high risk for CVS — and these patients come into your practice every day.
Patients of every age and occupation walk into my practice with CVS. We start to probe for potential issues by asking about computer use in our standard history form. We ask patients, "Do you use a computer?" and "How many hours a day?" If you don't ask questions like this, you fall into the classic "I'm just here for my usual checkup" trap and miss important opportunities.
If a patient history indicates that the patient uses a computer for 2 hours or more a day, I question the patient to reveal potential symptoms of CVS, such as headaches, trouble refocusing, burning "tired" eyes, blurred or double vision, and neck and shoulder pain.
I also ask patients questions about eyestrain. When I'm probing for information, it's better to ask about real-life situations than to ask patients to list their symptoms. For example, questions like "When do your eyes get tired?" and "Do you notice blurrier distance vision after long computer use?" often yield informative responses. However, even when patients answer with vague comments about "working too hard" or being "so busy lately," I can dig deeper to find out if their eyes are blurry or dry, as well as the activities and timing related to the symptoms.
When I suspect CVS, I explain the problem to patients. Their eyes are continually straining to refocus on the screen, and eventually symptoms develop. For a bit of "wow" factor, I use a PRIO Vision Tester (PRIO Corporation), which attaches to the reading rod and replicates the pixels of a computer monitor. If you don't want to use the PRIO Vision Tester, use a standard cross cylinder test at 22 to 24 inches and explain to the patient that you're taking very specific measurements to calculate the exact lens corrections for optimum computer vision.
Finally, I let patients with CVS know that we can make their work easier and more productive. The two-fold solution — ergonomic changes and computer lenses — mean less eyestrain and a more productive workday.
CVS is often part of a big picture that includes ergonomic problems at the computer. Only computer glasses address the focus fatigue that patients with CVS experience, but these changes to the work area and habits can help alleviate most other aspects of CVS:
■ Start with the screen. Many people use new flat-panel liquid crystal display (LCD) computer monitors, which have a higher resolution than early LCDs. The same is true of newer laptops. But patients using older LCD monitors or laptops may find that an upgrade helps their eyes. Most new monitors have a high resolution (a dot pitch of .28 mm or smaller). Patients should consider getting a desktop monitor that's at least 19 inches in size and look for a relatively large laptop display, at least for long-term work. In the rare case that a patient is still using a cathode ray tube (CRT) monitor, which has a lower resolution and eyestrain-inducing flicker, tell the patient his eyes and his energy bill will thank him for an upgrade.
No matter what kind of monitors patients are using, they should check the display settings. A "white" background shouldn't be blazing into their eyes or look gray. Patients should set the brightness to match the surroundings. They can also boost the contrast between the text and background and make sure they're viewing the text at a comfortable size.
■ Adjust the work area. Do you have the best lighting situation for your computer? Most people don't. In bright office cubicles or at home in a sunlight-filled office or on the sofa with a laptop, we don't use computers in the subdued lighting that's recommended. I tell my patients to reduce the lighting whenever possible and avoid bright light, whether it's from a desk lamp or a window. They can move the lamp, shade the window or keep the window at their side, never in front or back of them.
The same goes for sources of glare, such as shiny or bright-white surfaces. New monitors usually reduce glare, but if not, patients can get glare screens. They can also get anti-reflective (AR) coatings on their lenses to cut glare.
Other ergonomic changes to the workspace can help patients with CVS as well. Patients should adjust their chairs for proper posture and sit with their screen 20 to 24 inches away and 10 to 15 degrees below their eyes. They also might use a document stand to put papers they need to reference next to the monitor.
■ Hit escape. Patients need to give their eyes a break. First, to reduce the fatigue caused by continuous refocusing, they should look at something far away every 20 minutes or so. I tell patients this is the "20/20" rule. For every 20 minutes of work, take a 20 second break.
During their break, patients can do simple eye exercises, such as blinking or focusing near and far. By blinking slowly 10 times, they can counteract the effects of the infrequent or incomplete blinking they normally do in front of a computer. If dry eyes are a problem, I recommend a lubricating drop. If possible, patients can add a humidifier and redirect fans or vents to prevent dryness.
Every hour or so, patients should get up and walk away. They should stretch their muscles, walk around, get a drink or visit the restroom. Breaks exercise their bodies, relieve tension and give their eyes something normal to do, even if it's just for 5 minutes. They may even be more productive because they'll return to the computer feeling less fatigue.
Patients don't need to have full control of their environments to make most of these ergonomic changes. Even in a workplace with big fluorescent lights and a locked thermostat, they can make some changes to meet most of their needs — especially if they add computer lenses that relax the eyes.
Diagnosing CVS and determining the best treatment is a process. When I read the history and perform the exam, I'm asking questions to get a clear picture of how the patient uses a computer. We have a laptop in every exam room, and I ask patients how far they sit from the screen or I have them demonstrate how they sit in front of a monitor. I often explain that the patients' eyeglasses or contact lenses correct for reading or distance vision, but not the distance at which they view the computer.
I prescribe computer spectacles, which are designed to eliminate the eyestrain that results from constant refocusing on the computer screen. I tell patients that these "pillows for your eyes," or "stress-reducing eyeglasses," help their eyes relax and work less hard.
Sometimes, intensive computer users have already tried off-the-rack computer eyeglasses, but they tend to pick lenses that are too strong. I take a few minutes to show them the options and benefits and help them understand how prescription computer eyeglasses can help them.
Contact lens wearers may find that computer glasses help ease dryness as well as fatigue. I prescribe many single-vision lenses, but for patients with presbyopia, I might recommend multifocal computer lenses for the screen and closer objects, such as the keyboard. Anti-fatigue lenses, such as computer lenses, tend to have less peripheral distortion than other progressive lenses because of the design. Patients find them easy to adapt to, and they're great for hyperopes and early presbyopes who want a little more reading power without a full reading lens.
An anti-reflective coating is a good option to reduce glare. If patients work in a bright room and aren't able to adjust the lighting, they might benefit from a slight tint or an ultraviolet-absorbent coating.
I put patients in trial lenses and have them look at a laptop computer in the exam area to get an idea of how the computer lenses can help them. For patients with CVS, this second pair of eyeglasses is an easy decision. They spend hours every day on the computer, and they can immediately see the difference the eyeglasses will make. They complete the patient's needs, and some insurers cover the computer prescription. It's also an ideal addition for the patient whose regular and sunglass prescriptions are stable and don't need a change.
People are often amazed at the difference. They tell me, "I should have done this before!" Sometimes patients are getting information about computer eyeglasses for the first time and it seems very new or they don't fully grasp it, so they want to wait until next year. That works out fine, especially since they're thinking about those anti-fatigue computer glasses every time their tired eyes have trouble focusing on their computer screens.
Several manufacturers make computer lenses. Essilor Anti-Fatigue lenses are easy to prescribe, and it's easy for staff to understand how to measure for them. Essilor's Anti-Fatigue lens has a standard +.62 addition, regardless of what you prescribe for the top. You prescribe the top power you want for computer use, and the +.62 is standard. For example, if you write the prescription for +1.00D, then the maximum reading power will be +1.62D. With other computer lenses, there is often confusion. Some labs want you to specify full reading power, and then subtract power to arrive at the computer lens power. Other labs want you to prescribe the patient's distance correction and spectacle add, then specify, "Lab to calculate." Either way, you should try to establish a procedure for your office or you'll encounter issues when you make changes in subsequent years.
The two-fold solution — ergonomic changes and computer lenses — mean less eyestrain and a more productive workday.
The Business Side
As I mentioned, computer lenses make a good addition when a patient's regular prescription is stable, which means these specialty lenses are a new source of revenue. You'll also find that people who have been experiencing eye fatigue, dryness and difficulty focusing may be so pleased to find relief that they're willing to pay out of pocket for computer lenses.
These lenses create good buzz when patients tell their colleagues, "I love my computer glasses!" Word spreads from cubicle to cubicle that relief is available.
I also make an effort to keep patients educated through a newsletter that's sent out three or four times a year. Patient education is a vital tool to help separate your office and establish it at the forefront for your patients' needs. I want my patients to understand that I have the solutions to all of their visual needs. Simple headlines such as, "If you use a computer more than 4 hours a day, ask us about computer lenses," generate interest and inquiries. Our in-office video also informs patients that we can customize their eyeglasses for better computer vision. With all of these different avenues, patients come into the exam room having at least heard about computer lenses.
Training about computer lenses is available for you and your staff from manufacturer representatives. Use company resources, such as fitting guides and templates, to make sure the lenses will fit the frames correctly, and take advantage of free educational materials.
It's pretty simple to begin prescribing computer eyeglasses to your patients. After all, the lenses meet an unfulfilled need in a population that's spending hours every day in front of a computer, and those people are already in your chair. nOD
CVS Affects Kids, Too
It's no surprise that kids are spending hours on the computer: doing homework, playing games, surfing the Internet and communicating with friends. Just try to tear them away! But it's just that "glued-to-the-screen" effect that can cause CVS.
Children get involved in what they're doing and lose track of everything else. They don't know about ergonomics, so they use a home workspace designed for a much larger adult. They don't care about vague warnings of far-off health effects, so they spend hours staring at a screen and wearing out their eyes. In the past, many of those kidswould have been playing outside, focusing on near and distant objects. Now they're inside with CVS.
I like to ask kids, "What do you like better, math or reading? Spelling or reading? Gym or reading?" If they prefer math, spelling and gym and hate reading, then I know I may need to make reading easier. I do extra near-point testing to see how they use their eyes to read. I want to see the behavioral, perceptual focusing issues at close distances.
I also ask kids about computer use and explain to parents that computer eyeglasses are well suited for reading and homework. Computer eyeglasses can help kids boost their school performance so their results match their efforts — even if they keep playing video games.
|Dr. Wan is one of the managing partners in a multi-doctor practice in San Jose, Calif. He received his bachelor's degree from Pacific University in Oregon and went on to receive his Doctor of Optometry from Pacific in 1983. He is a contributing author on the topic of computer vision syndrome for the consumer website AllAboutVision.com.
1. American Optometric Association. "The Relationship of Computer Vision Syndrome to Musculoskeletal Disorders," Accessed online January 29, 2010 (http://www.aoa.org/x5378.xml).
Optometric Management, Issue: March 2010