If you're like many computer users, you may need a pair of glasses for your computer work that is different from your regular glasses, either with a different prescription or a different lens design.

Or, you might need computer glasses for a vision disorder that would not otherwise require correction if you weren't performing a demanding visual job like using the computer.

Bifocals or progressive addition lenses, usually prescribed for presbyopia, don't work well for computer work. The best solution for the presbyopic computer user is a lens that is specifically designed for the ergonomics of the computer workstation.

These special computer lenses are designed to accommodate the unique viewing distances and angles at a computer; they work for presbyopic computer users and can also work for others who require lenses for their computer. These lenses also work well for general office work.

It's important to have a good monitor for your eyes to perform efficiently and comfortably. Even on the best ones, the image is not as good as on a printed page.

The following tips should help you to select a soothing monitor:

1. Resolution is important, especially for extended work: the more pixels, the better. Monochrome displays usually have better resolution than color.
2. For color monitors, look for smaller dot pitches (less than 0.28 mm).
3. There is a good possibility that flicker beyond our ability to detect is causing visual difficulties. Higher refresh rates are desirable: at least 70 Hz.
4. Having a monitor capable of displaying high amounts of luminance (brightness) ensures that you can match the screen luminance to that of the screen's surroundings. Also, if you're going to use an antireflection filter to enhance contrast, you will want to be able to increase your monitor's luminance, because a side effect of the filter is decreased luminance.

The eyes lead the body. Since working at the computer is a visually intensive task, your body will do what is necessary to get your eyes in the most comfortable position -- often at the expense of good posture, causing musculoskeletal ailments such as sore neck and back.

Distance From Your Eyes

Although there is a wide range of acceptable viewing distances, depending upon the computer screen and tasks you're performing, most people are about 20-28 inches away.

If your viewing distance is outside of this range, it may indicate a visual problem (an eye exam would rule out this possibility) or it may be contributing to posture-related symptoms.

Height

Your eyes work best with a slight downward gaze; the center of the computer screen should be four to nine inches below your eyes. If the computer screen is higher or lower than this, it causes an awkward posture that contributes to sore neck, back, or shoulders.

If your screen is too low (more than 9" below your eyes), consider the following:

• Raise the computer screen. You can buy spacers, but old phone books also do the trick.
• Lower your chair, but don't allow the chair seat to become lower than the bottom of your knee cap.

If your screen is too high (higher than 4" below your eyes), consider the following:

• Lower the computer screen. If your monitor is on top of the CPU, consider moving the computer to the side or under your desk and placing the screen directly on the desk surface. If this results in your screen being too low, prop it up as suggested above.
• Raise your chair, taking care to keep your feet on the ground.

Straight Ahead

Your computer screen and other work should be straight in front of you so that you don't have to look sideways or twist your body or neck to see them. Use a document holder to locate your reference material close to the screen.

Regularly looking sideways at your computer causes soreness in your neck, back and/or shoulders.

Glare sources are a particular problem for computer workers because we're looking horizontally in the room. This results in the light fixtures and other glare sources being closer to our fixation point, compared to yesterday's office worker, who usually looked down at the desk.

Bright, open windows pose the same risk as overhead light fixtures. Other sources of brightness are: white paper on the desk, white desktops and desk lamps aimed toward the eyes, or which illuminate the desk area too much.

Overhead Lights and Desk Lamps

Turn off any lights that are bothering you (making sure to check with your co-workers). Many offices have two wall switches controlling the lights; each switch turns on half of the bulbs in the fixtures.

If you find you can't do without your desk lamp, try putting in a lower wattage bulb.

If possible, have your business retrofit the fluorescent light fixtures with parabolic louvers, which direct light straight down (instead of into everyone's eyes).

Windows

Use blinds or drapes on the windows. If the view out of the window is considerably brighter than the objects in the room (as it almost always is), the window is serving as a glare source. Usually, the best solution is to use blinds, adjusting them so that the light goes up toward the ceiling, or sideways (away from your eyes).

Your Desk

Rotate or move your workstation so that the lights or windows are not in your field of vision while you're looking at your computer. It's best if the windows can be straight to your side. If the windows are in front of you, they can cause discomfort; if they're behind you, they can create reflection problems on the screen.

Reflective Surfaces

Avoid bright, reflective surfaces. Desktops and other furnishings should have a matte, medium reflective surface. Ceilings should be white and walls should be medium light.

Filters

The most common and usually the most effective way to reduce reflections is to place an antireflection filter over your screen. The primary purpose of these screens is to decrease the luminance of the blacks (make the blacks blacker), thereby increasing the contrast. Most are either mesh or glass/plastic.

The mesh filters are black cloth; they're quite effective at making the screen blacker and are usually less expensive than glass and plastic filters. However, looking through the mesh reduces the resolution of the characters on the screen.

Glass or plastic filters work by passing light through twice; the luminance of the reflections is reduced more than tenfold. This greatly improves the contrast, with no significant loss of resolution. Some glass or plastic screens have a polarizing property that can provide further improvement.

A visor is one way to block overhead light.

All antireflection screens reduce screen brightness, so you'll need to increase the brightness on your computer. Adjust it so that it is similar in brightness to the immediate visual surroundings. Some monitors may not have enough range of adjustment to compensate for the effects of the filter.

Block-Aids

You may be able to move a partition to block bright lights.

Wear a visor while working at the computer: this effectively blocks overhead lights.

A hood is like a visor you put on your screen. It extends four or five inches, protecting both the top and the sides from light.

Computer vision syndrome also includes musculoskeletal problems: sore back, neck, shoulders and wrists.

The following tips should provide some relief, but see your doctor about any persistent problems.

Keyboard and Mouse

The keyboard and mouse should be lower than your elbow. If they are higher or too far away, your shoulders have to hold up the weight of your arms while you are working, resulting in shoulder, neck and backache. A keyboard extension shelf can help; if you can't get one, raise your chair -- but make sure that your feet remain firmly on the floor.

To reduce the stress that typing places on your wrists, keep your wrists relatively straight. It is natural to have your wrists bent slightly upward and outward while typing.

Consider using a wrist rest in front of your keyboard in order to help keep your wrists straight. The wrist rest should be soft and arranged so that your wrists float just above it while typing. Your wrists should not rest on it during typing -- only when you are resting.

Chair

Adjust the height so that your feet are firmly on the ground and the angle at your knee is 90 degrees or greater (i.e., the seat should be higher than the bottom of your kneecap). A footrest is helpful if your chair needs to be higher in order for you to use your keyboard and screen.

Sitting is very stressful on your lower back, but you can minimize the effects by maintaining the normal curvature in the hollow of your back while you work. You should concentrate on maintaining this posture while working -- it quickly becomes common practice.

If your chair has adjustable lower back support, adjust it so that it provides firm support. A cushion or rolled up towel can also provide lower back support.

If you have adjustable arms on your chair, adjust them to provide arm support while you are typing.