How to achieve office ergonomic
Office ergonomic sometimes has been igonored, and people dont realize inappropriate designed computer workstation and/or bad work habits can result in serious health problems, such as discomfort in the back, neck and shoulders, hands and wrists, as well as headaches and eyestrain. If you experience any of these symptoms while working, should rethink about office ergonomic and seek for medical help.
To solve this issue is not too complicate. Proper workstation setup and work practices can eliminate discomfort and even prevent it from occurring in the first place! Simple adjustments to office equipment can work wonders, making work more comfortable and more productive.
What To Look For In A Chair
Starting from the bottom and moving upwards:
The chair should have at least 5 castors at the base to ensure stability. Chairs with five castors are more stable than four castor chairs. Four castor chairs are easier to tip over.
The seat should be able to adjust until your thighs are parallel to the ground. Shorter/taller users may need different height cylinders. If you are unable to adjust your chair heigh properly, contact the chair manufacturer for a replacement cylinder. Adjusting the chair too high places more pressure than necessary on the backs of the legs, reducing circulation. If the chair is too low, a smaller portion of the legs is in contact with the chair and the pressure on that area is correspondingly greater.
- The seat pan depth should be adjustable to provide a fist-width to three-finger gap between the back of the calf and the front edge of the seat pan. If the seat pan is too shallow, all the pressure from sitting is placed on a small part of the thighs, which may lead to discomfort. If the seat pan is too deep, it will either be difficult to use the backrest or the front of the seat will put pressure on the back of the nerves and tendons at the backs of the knees.
- The seat pan should be able to tilt backwards and forwards. Changing your posture thoughout the day is positive because when you change postures, the loads of sitting shift to different parts of the body, allowing your body to recover from extended static postures.
- The seat pan should have a waterfall (rounded) front edge. Sharp corners, even when they’re made of padding, increase the pressure on the backs of the thighs. A rounded front edge distributes the pressure over a larger area.
Firstly, armrests are optional. Even with the range of adjustments found in many of today’s armrests, there are some places where armrests will interfere with work.
- The armrests should be adjustable in height. If the armrests are too high, you might have to shrug your shoulders in order to use them, which could fatigue your shoulders and back. Conversely, if they are too low, then you might end up leaning on one armrest.
- They should be rounded on the edges. Sharp corners, even when they’re made of padding, increase the pressure on the arms. A rounded edge distributes the pressure over a larger area.
- Optional: most armrests are spaced too widely apart for the user to use them comfortably. Armrests that are width-adjustable to slide over the seat pan until they are right under the elbow or armrests that pivot inwards (the kind that can pivot almost all the way around are preferable) are much more functional than simple height adjustable armrests. If the armrests are spaced too far apart, they will not be directly under the elbows. In order to use the armrests, users have to hold their arms slightly away from the body. This reach can fatigue the shoulder muscles.
The backrest height should be adjustable so the lumbar support can be fitted into the low back. The backrest should mirror the shape of your back to provide support. The weight of the upper body is supported by the spinal vertebrae at the bottom of the lumbar curve (curve at the small of your back). These same vertebrae are the most common origins of back pain. Using the backrest to support the lumbar curve relieves some of the pressure on the frequently injured vertebrae.
- The backrest should be able to recline independently of the seat pan and be set at a fixed reclined angle. It is acceptable to sit upright or recline slightly in your chair as long as the backrest is designed for reclined seating. A slightly reclined posture opens up the angle between the hips and trunk, which decreases the stress placed on the low back.
Why Not To Use An Exercise Ball For A Chair
Considering using an exercise ball as your office chair? Think again. What may seem like a good idea to you or others is actually not recommended. Read the following articles for further information:
- Replacing Office Chairs with Exercise Balls by Heather Ritz
- Opinion: Balls as Office Chairs a Bad Idea
Setting Up My Chair
Start out adjusting a chair from the ground up. Start with the height and move up from there. While adjusting the chair, worry first about getting the chair adjusted to fit you. Afterwards, look at things like the height of the desk, keyboard, etc. Too often, people adjust a chair too high so they can reach the keyboard rather than properly adjusting the chair and adding a keyboard tray to move the keyboard to the correct height.
Start by adjusting the height until your thighs are parallel to the floor. Stand in front of the chair and adjust the height until the top of the seat pan is at the height of the bottom of your kneecap. Then, sit in the chair and make small height adjustments until your thighs are parallel to the ground. Sit in this position for a while before making any further changes in seat height. When you have become accustomed to this height, adjust the chair height up/down 1-3 inches until you find a location that is comfortable for you while seated (don’t worry about that keyboard height yet!).
Adjust the seat pan until you have about three fingers to a fist’s width of room between the back of your calf and the front edge of the chair when your back is touching the backrest. If the seat pan is not adjustable and the pan is too deep, add padding to the backrest (a towel over the backrest of the chair or a backrest cushion) to shift you forward in the seat while maintaining contact with the backrest. If the seat pan is too shallow, start looking for a new chair.
There are three basic postures. The standard posture calls for a level seat pan so it is not necessary to adjust the tilt for this posture. Likewise, the reclined posture can have the seat flat as well. However, some people prefer to have a very slight backward tilt on the seat pan to hel keep them in the seat. In the forward tilt posture, the seat pan is tilted forward 5-10°. Start by raising the overall height of the chair a few inches, and then tilt the seat pan forward.
The lumbar curve on the backrest should fit into the small of your back. Start by raising the chair back as high as possible and then move the backrest downward in small steps until it feels most comfortable. If the chair doesn’t have enough lumbar support consider adding a lumbar pad to the chair. Make sure the extra pad doesn’t make the seat pan too short!
In the standard posture and forward tilt postures, the backrest should be straight up. If it feels as though the chair is pushing you forward, adjust the backrest back until you feel upright. In the reclined posture, the backrest should be reclined slightly. When seated, the angle between the thighs and back should be more than 90°.
As previously mentioned, armrests can sometimes interfere with work. If they prevent you from pulling up to your desk or reaching for the mouse, either lower them until they are out of the way and don’t use them, or have them removed. Armrests are “rests” not “supports”. Typing with the arms constantly on the armrests is not recommended.
Sit in the chair with your arm bent 90° and raise the armrest until it is directly under your elbow. Repeat the process with the other arm and then check that the armrests are the same height.
Some armrests pivot or slide inwards, allowing you to change the angle and width of the armrests. Adjust the armrest inwards until it is directly under your elbow while your upper arm/shoulder is relaxed. You should not have to reach your elbows outward to reach the armrests. If the armrests pivot, pivot them slightly inwards so they are underneath your forearms when you reach inwards to the keyboard.
This video guides the viewer through the steps involved in ergonomically adjusting their task chair to their workstation and body dimensions. Special thanks to Kim Haley and Larry Daw.
What To Look For In A Footrest
Use footrests as a last resort. Footrests are a way to shift postures or provide support for the feet if the chair cannot be lowered. Unfortunately, using a footrest when the chair is too high provides only one place for the feet to rest. The seated person only has the footrest and the castors under the chair as places for their feet and this limits the postures they can shift through throughout the day. The preferred solution is to add a shorter cylinder to the chair (see the chairs section), and lower the desk height until the desk surface is approximately 1 inch above seated elbow height.
A footrest should be height adjustable. Adjust the footrest until the thighs are parallel to the floor +/- 1-3 inches.
When using a footrest, be sure to shift postures frequently. Some footrests have a rocking feature that allows the user to rock the footrest, increasing circulation and helping avoid static postures. The rocking action on all-plastic footrests tends to wear out quickly, so look for durable models.
What To Look For In A Keyboard Tray
The purpose of a keyboard tray is to change the height and angle of the keyboard without interfering with how the user uses the keyboard and mouse. Therefore, the tray should be easy to adjust, have enough room for the keyboard and mouse and not prevent the user from typing with the keyboard at forearm length from the body.
The tray should be height adjustable until the mouse and keyboard are at or slightly below elbow height. Avoid keyboard trays that require unscrewing a knob every time the height is adjusted. Knob-adjusted trays discourage users from making small adjustments in height and the knob, often located under the tray, may hit the user’s knee and prevent them from sitting close enough to the keyboard and mouse to use them properly. Many newer trays have lever-less mechanisms, which allow users to adjust tray height by lifting the front edge and either pulling up on or pushing down on the back edge.
The tray should be angle adjustable to align the forearm with the keyboard. Often this will require a “negative tilt” where the front of the keyboard is higher than the back. For some users, it may be necessary to adjust the angle of the mouse surface as well to prevent the mouse from rolling off the tray.
The tray should have space for the mouse beside the keyboard at about the same height.
If the tray comes with a wrist rest, it should be soft foam or gel and be removable. Not all keyboards will fit on a standard keyboard tray with the wrist rest attached.
Setting Up My Keyboard Tray
Sit upright in the chair and bend your elbow 90°. Hold your open palm down and raise the keyboard tray until the keyboard is just under your fingers. Keep the keyboard at this height or slightly lower as desired. Reach to the side and check to be sure the mouse is just under your hand as well. Some keyboard trays have mouse attachments that attach to the side and below the keyboard. If this places the mouse too low, put additional mousepads under your mouse until it is at approximately the same height as the mouse.
Hold your hand, palm open, over the keyboard. Tilt the tray to align the angle of the keyboard with the angle of the forearm. If the keyboard is below elbow height, this will require a negative slope where the spacebar edge of the keyboard is higher than the back edge. In most cases, the keyboard will be either flat or tilted at a negative slope. Do not use the feet on the back of your keyboard or tilt the tray at a positive slope unless you are seated in a reclined position. Even when reclined, start with the keyboard flat before trying a positive tilt.
Place the mouse beside the keyboard tray and at about the same height. On trays where there is room for the keyboard and mouse on the same tray, place the mouse beside the keyboard. On trays where there is a mouse attachment attached underneath the tray, check the mouse height in the same way as the keyboard height. Additional mousepads are a good way to raise the mouse. Some trays have a mouse attachement above the keyboard. These attachements slide or pivot to cover the numeric keypad on the right hand side of the keyboard and reduce side reaching to use the mouse. Keep these trays pivoted over the numeric keypad when not using the keypad.
What To Look For In A Keyboard
There are many keyboard designs available. This page will cover the two most common keyboard designs. The standard flat keyboard and the split keyboard. For a more in-depth review of keyboard designs, see Ergonomics of Alternative Keyboardsand the National Institute for Occupational Safety and Health brochure on alternative keyboards.
Standard Flat Keyboard
This is the standard rectangular keyboard with a numeric keypad on the right hand side.
These keyboards are split in the middle (between the g and h keys) and the halves are moved at an angle to each other. The theory is that angling the sides will keep the wrists straight. These keyboards are often tented upwards slightly in the middle.
Many keyboards have built-in or detachable wrist rests. These rests are usually hard plastic and, where possible, should be removed. If the wrist rest is not removable, keep in mind that these are wrist “rests,” not wrist “supports”. They should be used only during pauses while keying.
Setting Up My Keyboard
The number pad creates an optical illusion when aligning the keyboard and monitor, particularly with standard keyboards. The monitor is usually lined up with the center of the entire keyboard (apporximately the ‘;’ key). The user, however, sits lined up with the center of the letters portion of the keyboard (approximately the ‘g’ and ‘h’ keys). This causes the user to either twist slightly to face the monitor or sit centered to the monitor and reach to the side to use the keyboard. When seated at the workstation, align the “gh” keys with the bellybutton and also check that the “gh” keys are centered with respect to the monitor.
What To Look For In A Mouse
The first decision to make is what kind of input device to get. Users grip standard mice and move them to move the cursor on the screen. With a trackball, the user rolls a ball mounted on a stand to get the same effect. Touchpads require the user to move a finger on a small touch-sensitive square to move the cursor. Other input devices mount in front of the keyboard, use a pen on a large touch-sensitive square or even combine hand gestures to interpret commands.
After deciding on the input device, look for the features it offers and how well it fits the hand.
Common retail mice are manufactured in different “standard” sizes depending on the manufacturer. Most superstores have different mice on display in the store to try out. Try them out to see how well they fit the hand. A good mouse should partially “fill” the hand while gripping it. If you find yourself gripping the mouse with your fingertips or squeezing it between thumb and pinkie or thumb and ring finger, the mouse is probably too small.
Trackballs are stationary devices, so they require less room to use than the standard mouse. They are normally larger than a mouse and may support the hand better. Look for trackballs with the ball located in the center (side-to-side) of the device. Avoid trackballs where the ball is manipulated using the thumb as this may place undue stress on the thumb.
Touch pads are compact input devices similar to those used in some notebook computers. Like trackballs, they are stationary. Touchpads are used by moving one finger along the pad.
So-called ergonomic mice have one or more design feature(s) intended to make the mouse more usable. Often these mice are curved along their length or raised on the thumb side to support the hand in a handshake posture. The drawback of these mice is they are usable only by one hand. Symmetric mice can be switched between the right and left hands without difficulty whereas the shaped mice require the user to assume an unusual grip if using the mouse with the hand the mouse was not designed for. Beyond that, check to be sure the mouse fills and supports the hand without requiring pinching with the fingertips.
About Wrist Rests
Wrist rests are intended to promote straight wrists and reduce pressure on the wrist by providing a soft surface to rest upon. However, research studies by Parsons (1991), Paul and Menon (1994) and Horie et al. (1993) indicate that foam wrist rests create similar pressures on the wrist as not having a wrist rest. Wrist rests that are higher than the keyboard or too narrow can actually be worse than no wrist rest at all.
Like chair armrests, wrist rests are “rests”, not “supports”. Too often, users support their wrists with the wrist rest continuously while keying and mousing. In addition to exposing the wrists to constant pressure, this static position forces the typist to stretch the fingers and bend the wrist to reach keys at the sides of the keyboard.
Wrist rests are best used when there is a sharp edge or hard surface the user is constantly coming into contact with. They should be used to rest the wrists during pauses while typing and not used as a continuous support.
What To Look For In A Wrist Rest
Look for a gel wrist rest that does not have a stiff plastic casing. Foam wrist rests do not distribute pressure as well as gel, and can create pressure points at the edges. Some gel wrist rests are designed like a wrist rest in a hard plastic box with an open top (where the wrists rest on the gel). Avoid this kind of wrist rest as the casing can come into contact with the wrists and create a pressure point.
Choose a rest that is no higher than the front edge of the keyboard. Wrist rests that are higher than the keyboard force the user into awkward postures to properly use the keys.
Wide, slightly rounded wrist rests provide the best distribution of pressure. Wrist rests with a pronounced peak (such as many mouse wrist rests) concentrate the weight of the wrist over a small area and are unsuitable.
What To Look For In A Monitor
Monitors now come in two types: CRT (the traditional “box” monitor) and LCD (the thin, “flat panel” monitor). CRTs are less expensive and take up more space.
Naturally, the larger the monitor size, the more expensive the monitor. 15″ monitors are the minimum recommended size, though 17″ monitors are becoming increasingly common. CRT monitors are measured along their diagonal and include some space that is hidden by the monitor’s casing. LCD monitor measurements only refer to viewable area.
Dot pitch affects how clear the monitor image is. The smaller the dot pitch, the better. A dot pitch of 0.27 is the lowest recommended quality, while 0.26 or lower values are preferable. Monitors with better dot pitch are better able to support the high resolutions demanded by many of today’s computer programs without flickering. Such flickering can create eye fatigue and discomfort.
This applies to CRT monitors. Refresh rate is the frequency with which the image on the screen is redrawn. 60Hz is the standard refresh rate, however many people are sensitive to refresh rates this low and are affected by the resulting screen flicker. 70 Hz and higher refresh rates are recommended.
Setting Up My Monitor
The monitor should sit directly in front of the user, and in line with the “gh” keys on the keyboard.
The monitor should be tilted back, so the bottom of the screen is slightly closer to the viewer than the top.
The top of the screen should be at or below eye level. If you notice that you tilt your head back while viewing the screen, think of ways you can lower the monitor. First, check to see if the CPU is underneath the monitor. Call 919-962-HELP and ask if the CPU can be moved to its side safely. If so, move the CPU from under the monitor and place it beside the monitor. As (919-962-HELP) if a special attachment is needed inside the computer’s CD/DVD drive to hold discs in place while the computer is on its side.
Start by placing it at arm’s length. Adjust the monitor slightly closer or further away as your eyes dictate. If you find the monitor is only viewable extremely close or far away, consult your optometrist as you may require corrective lenses (or a change in prescription) to see the monitor properly.
If the job requires privacy while working, instead of rotating your monitor to one side, consider a privacy screen, which will allow you to keep the monitor directly in line with you and the keyboard.
Keep the computer screen clean by wiping it very lightly when needed with a damp paper towel or monitor cleaning solution.
What To Look For In A Glare Screen
When shopping for a glare screen, consider what you need it for. Glare screens reduce light reflected into your eyes from the screen and reduce washing out of images on the screen. Privacy screens are used to prevent others from seeing the computer screen while standing to the side of the computer. Some screens combine both features.
Use a glare screen only when you cannot position the monitor away from glare-producing light sources or turn off lights that shine on the screen (see setting up my monitor and lighting). Using a glare screen is similar to wearing a pair of sunglasses while looking at the monitor. Everything is darker, including images on the screen!
Polarized vs. Nonpolarized
Look for a glare screen that uses a polarized surface to reduce glare. This technique is used on some sunglasses to reduce bright lights while maximizing the visibility of other objects.
Match your monitor privacy needs to the situation. Some privacy screens require the user to be directly in front of the screen. Others prevent viewing from the side. If the information on your monitor is sensitive and people frequently pass behind your monitor, a more restrictive privacy screen is in order. Otherwise, consider one that allows a wider viewing angle so the person sitting at the computer can shift positions without the privacy screen blocking out their vision.
Setting Up My Glare Screen
After putting the screen in front of the monitor, check to see if reflections on the screen are reduced. Next, look through the screen to the monitor. Is the monitor darker? Adjust the brightness and contrast controls on the monitor until you can comfortably view the monitor again.
What To Look For In A Document Holder
The purpose of a document holder is to hold reference documents as close to the computer screen as possible, and at about the same angle. This will eliminate a twisted working posture, and also put the document at an easier-to-read angle. Constantly reading from a hard-to-read angle can be hard on the eyes.
Document holders usually either clip to the side of the monitor, sit beside the monitor, or rest in front of the monitor.
Clip to the Side Document Holders
These document holders attach to the side of the monitor and usually are designed to hold only one or two sheets of paper. These document holders are useful for single, infrequently changed sheets of paper such as phone lists. However, for documents that are frequently changed, such as during data entry, or tasks that require making notes on the document, they are not well suited.
Beside Monitor Document Holders
These document holders rest beside the monitor on the desk. Look for an easel style monitor to allow several documents to be placed on the document holder simultaneously. These document holders are also useful for writing notes on the document.
Under-Monitor Document Holders
These document holders usually rest between the keyboard and the monitor and directly in front of the user. These document holders allow the user to easily make notes on documents. Wider under-monitor document holders may be used as a way to increase desk space.
When Do I Need A Headset to achieve office ergonomic?
Users who frequently use the phone and computer simultaneously or are on the phone for extended periods of time should consider a headset. Headsets attach to the head like a single headphone with a mouthpiece or attach directly to the ear. Headsets reduce the tendency to cradle the phone and allow the user to work with both hands while conversing on the phone.
What To Look For In A Headset
Headsets are either cordless or corded and both come in traditional headphone and over-the-ear configurations. In addition, the UNC phone system is compatible with specific headsets. Check with the manufacturer or retailer of any headset before purchasing.
Cordless vs. Corded
Cordless headsets compatible with the UNC phone system come in one- and two-line configurations. Corded headsets are compatible with phones using any number of phone lines.
These recommendations are for users who frequently travel and spend substantial time using a notebook computer while on the road.
Transporting notebook computers in carrying cases slung over one shoulder places a lot of stress on the shoulders and neck. If your notebook, bag and assorted components in the bag weight 10 lbs or more, consider using a back with wheels and a handle that can be pulled behind you.
When purchasing a notebook computer, consider the weight of the entire system, not just the notebook alone. Some ultralight notebooks require so many additional accessories that they end up weighing the same as a regular notebook.
Keyboard and Monitor too Close to Each Other
When computers were first designed, the keyboard and monitor were very close to each other. This caused users to either hunch down to see the monitor, hold their arms uncomfortably up to reach the keyboard, or a combination of both. As computer design advanced, the designers separated the monitor and keybaord so they could be more comfortably placed. Notebook computers, in the name of portability, step back into the bygone era of cramped computing and place the keyboard and monitor right next to each other. In addition, to save space, the built-in input device in most notebook computers has been designed to reduce space. Small trackballs, touchpads and pressure sensitive “eraser head” style input devices are common on many notebook computers. These devices are often too small to comfortably use or require awkward hand postures.
Solution: portable keyboard/external mouse. There are many portable keyboards available. These keyboards range from regular keyboards that fold in the middle for travel to flexible roll-up keyboards. When purchasing a portable keyboard, look for keyboards with full-size keys and ask yourself if you need the numeric keypad to the right of the keyboard. If you don’t need it, you might look for a keyboard without the keypad to save space and weight! Most external, desktop-style input devices are small and light enough to travel with you. Do not sacrifice comfort for size when looking for a traveling input device. If you choose a mouse, consider an optical mouse. Optical mice do not need a mousepad to operate correctly, making them more versatile for use while traveling. Note: Some notebooks only have one PS/2 port. PS/2 ports are most commonly used for keyboards and mice. If you wish to use an external keyboard and mouse with a notebook, you may need to use a notebook splitter (a Y-shaped connecter that allows 2 PS/2 connections to plug into a single PS/2 port) or use a USB mouse or keyboard and use the USB port and the PS/2 port. For two USB devices, similar splitters exist for USB.
The keys on many notebook computers are smaller and closer together than standard-sized keys. This makes the overall span of the keyboard smaller and cramps typing.
Solution: Portable keyboards. There are many portable keyboards available. These keyboards range from regular keyboards that fold in the middle for travel to flexible roll-up keyboards. When purchasing a portable keyboard, look for keyboards with full-size keys and ask yourself if you need the numeric keypad to the right of the keyboard. If you don’t need it, you might look for a keyboard without the keypad to save space and weight! Most external, desktop-style input devices are small and light enough to travel with you. Do not sacrifice comfort for size when looking for a traveling input device. If you choose a mouse, consider an optical mouse. Optical mice do not tneed a mousepad to operate correctly, making them more versatile for use while traveling.
Note: Some notebooks only have one PS/2 port. PS/2 ports are most commonly used for keyboards and mice. If you wish to use an external keyboard and mouse with a notebook, you may need to use a notebook splitter (a Y-shaped connector that allows 2 PS/2 connections to plug into a single PS/2 port) or use a USB mouse or keyboard and use the USB port and the PS/2 port. For two USB devices, similar splitters exist for USB.
So far, the term “notebook” has been very deliberately used instead of “laptop”. Some notebooks can get very hot. Working on a notebook computer exposes the thighs to that heat. The thighs are the largest muscels in the body and have a large blood supply. Blood flowing though the thighs picks up that heat and carries it thoughout the body. Not only to the legs start to overheat but the entire body gets warmer. In some cases, notebook computers can put out enough heat to have severe consequences.
As A Desktop Replacement
In some offices, the notebook computer has entirely replaced the desktop as the primary computer. Sometimes the notebook travels between a home office and a work office, in which case read the section on notebook weight.
Keyboard, Mouse and Monitor too Close to Each Other
Notebook computers can be used as a replacement for desktop systems. However, they are not stand-alone replacements. The keyboard and monitor on a notebook are too close together. When computers were first designed, the keyboard and monitor were very close to each other. This caused users to either hunch down to see the monitor, hold their arms uncomfortably up to reach the keyboard, or a combination of both. As computer design advanced, the designers separated the monitor and keyboard so they could be more comfortably placed.
Solution: External Keyboard/Monitor. Do the same with a notebook replacing a desktop as you would with a desktop: add a keyboard and possibly a monitor. If the notebook monitor is large enough, the notebook monitor can be used. Be sure to set up the monitor in the same way you would a stand-alone monitor (see monitors). Use whatever external keyboard and mouseyou are most comfortable with.
Note: Frequently moving the notebook requires plugging/unplugging many cords every time the notebook is used. If you frequently unplug your notebook computer for travel, consider a docking station or docking bar. Docking stations provide ports for keyboard, mouse, power, etc., that stay plugged in even when the notebook is not docked. The notebook snaps into the docking station and instantly has access to everything plugged into the docking station. Docking bars are far less expensive than docking stations but offer fewer features. If you only occasionally move the notebook, it may be more economical to plug and unplug all of the peripherals. However, some notebooks only have one PS/2 port. PS/2 ports are most commonly used for keyboards and mice. If you wish to use an external keyboard and mouse with a notebook, you may need to use a notebook splitter (a Y-shaped connecter that allows 2 PS/2 connections to plug into a single PS/2 port) or use a USB mouse or keyboard and use the USB port and the PS/2 port. For two USB devices, there are similar splitters for USB.
Many offices have more light than is required to use a computer. Your work area should have moderate, indirect lighting free from sources of glare.
There are three types of glare: Direct Glare, Indirect Glare, and Contrast Glare.
Direct glare comes from lights that shine directly into the eyes. Direct glare usually comes from sunlight shining though a window behind the monitor and directly into the eyes of the viewer. Sometimes poorly positioned desk lights will also shine directly into the viewer’s eyes.
Try to place the monitor perpendicular to windows and light sources. Point lamps at walls or the desk to diffuse the light source and keep the light from shining directly into the eyes. Be careful when shining lights onto a desktop. Some desks are highly reflective and can cause indirect glare.
To test for direct glare, use your hands to shield your eyes from light from above you and to the sides (windows and lights). If your eyes feel more comfortable shielded, look for light sources that could be shining into your eyes. Selectively shielding your eyes (i.e. only from one side for example) can give you ideas on where to look for the offending light source.
Indirect glare results from light bouncing off an object (such as the monitor) and into the eyes. Indirect glare on monitors is seen as reflections in the monitor (can you see your shirt in the monitor? What about the lights?) or as white spots. Desks, brass lamp bases and other reflective objects can be sources of indirect glare. Light can even bounce off a computer user wearing a light colored shirt, onto the screen and back into the user’s eyes. A great way to check for Indirect Glare from the computer screen is to turn off your monitor and examine any reflections visible on it.
Contrast glare is frequently overlooked as a source of glare. Contrast glare results when a light colored object (monitor screen, for example) is next to a dark object (the dark border on many LCD screens). The retina is simultaneously trying to become larger and admit more light (to see the dark object) and become smaller to admit less light (to see the light object). To test for contrast glare on the monitor, take a neutral colored piece of paper (file folders work well) and tape a border of paper around the outside of your computer. If your eyes feel better with the border around the computer, it’s a good bet the border was a source of contrast glare. It is also a good idea to combine this test with the other tests for direct glare and indirect glare.
Short, frequent rest breaks are more beneficial than longer, more infrequent ones. Sitting for more than an hour without moving can put stress on the body due to the static posture that you are forced to sustain. Breaks can be as simple as standing up and walking around your desk three times, or even simply yawning. When you sit back down, you’ll be in a completely new posture.
We recommend taking about 20 seconds to 1 minute of break every 30 minutes. You should also break up your sitting period by walking to the water fountain, printer, etc.
Exercises for office ergonomic
Have a break each 15mins to to some tension relieving exercises is good for your health, especailly when doing them at the beginning of each day.
Here are some other exercises:
- Clench your hand into a fist and release, fanning out the fingers. Repeat 3 times.
- With elbows straight, bend your wrists down as far as they will go, hold for 3 seconds then extend your wrists back as far as they will go. Do 5 times.
- Stand up straight, place your hands on your hips and bend backwards at the waist, gently. Do 5 times.
- Touch the fingertips of your hands together just behind the top of your head without letting your hands touch your head, move your elbows in a backward direction, hold 5 seconds then relax. Do 3 times.
- Tuck your chin in while keeping your eyes level; hold 3 seconds and then relax. Do 5 times.
- Roll your head in circles, stretching more toward each shoulder. Do 5 times.
- Eyestrain tip: Blink often, and take frequent rest pauses; close your eyes for a minute, refocus by looking away from your monitor at something in the distance, and roll your eyes up and down, left to right.
This article is published by University of North Carolina at Chapel Hill at https://ehs.unc.edu/workplace-safety/ergonomics/office/