DIGITAL ERGONOMICS AND LIGHTING

Screen Glare- Glare is one of the main problems associated with digital device use, and one of the easiest to fix. Since the front surface of the screen is flat, light can easily reflect from this surface into your eyes. How can you tell if you have glare? For a computer, simply turn off your monitor. If you can see reflections of lights or other objects in the screen, you have glare. Reflected images on the computer screen, perhaps from a window or a lamp, will cause the eyes to focus back and forth between the screen and the reflected object. This affects how well you see what is on the screen and will tire the eyes rapidly, preventing them from seeing clearly as the day progresses. 

Reducing or eliminating screen glare is simple and easy. In combination with reduced Office Glare (covered in the next section) a slight change in the angle of the screen should help. Also, for a laptop or desktop computer, make sure that your desk has the office windows to the side, rather than to the front or behind, so that the light can’t shine directly onto the screen. 

Finally, while anti-glare screens are available for both desktop and laptop use, they must be kept scrupulously clean and will slightly reduce the contrast on the screens. This would be a final choice should other environmental changes not be practical. 

Office Glare- This type of glare doesn’t reflect off the screen, but is either reflected off of items in your office or by light shining directly at you. These reflections increase the amount of light entering the eyes. When light levels become too high for you to tolerate you try to decrease the amount of light entering the eyes by squinting. 

The easiest way to tell if direct office glare is a problem is to simply put your flat open hand over your brow and then on each side of your face. If in any of these positions decreases the light and makes you feel more comfortable, office lighting from windows, lamps, or ceiling lighting needs to be changed either in position or amount so that it is no longer bothersome. 

In addition, if you have a desk lamp to illuminate papers or items on your desk, be sure that the bulb cannot be seen from your natural sitting position. If you can see it, or if the light itself is too bright, a repositioning of the lamp needs to be made so that it illuminates your work desk, but does not shine into your eyes.

Also, understand that there are many things you can change in your office setting and some that you cannot (window location, etc.). Change the things that can be changed to minimize their effect on you and your eyes.

Room and Office Lighting– Let’s expand our lighting discussion to talk about the environment that surrounds the digital device. While cell phones, laptops and tablets can be viewed in a great variety of settings, some general rules can be applied just as they do to stationary devices, such as desktop computers.

Again, understand that there are certain aspects of the visual and digital environment that you can’t change. You cannot walk into your manager’s or owner’s office and simply state, “I want the lighting changed over my desk and I’m moving my desk to change the lighting in my workspace” if either affects those around you or cannot be done economically. So, as I stated before, change what you can and live with what you cannot.

Let’s start with the ceiling lighting and work our way down.

Ceiling lighting may be dictated by the building owners or by the owners of the office, if they are not one and the same. Many office designs are based on what is aesthetically pleasing and not what is ergonomically sound. However, there are some general statements that can be made.

Fluorescent lighting is cheap and puts out a great deal of light. However, it is also the poorest choice for digital device users. This is due to the fact that not only are the devices self illuminating, that is, again, a source of light in and of themselves, but because fluorescent lighting in many cases exposes the worker to excessive light. The higher the ambient lighting, the more tendency there is to increase the brightness of the digital device. This is to try and neutralize the brightness both on the device screen but also the light entering the user’s eyes. And most fluorescent environments do not allow for dimming of the lights or reducing the areas of lighting.

The most common alternative to fluorescent lighting is LED lighting. While this saves energy and gives more uniform lighting, there are some drawbacks. LED lights have a higher output of what is termed, “blue light” and ultraviolet light than other sources. Blue light is a part of the spectrum that suppresses Melatonin production in the body. Melatonin helps the individual to achieve better and sounder sleep. When there is a depletion of Melatonin some individuals find it harder to fall asleep. Looking from a practical point of view, the presence of blue light sources during the day may actually help the individual stay awake and alert giving them a better opportunity to do their work. It is the depletion of Melatonin at night that is of concern. More of this, and a discussion of ultraviolet light will be discussed in the next session “Visual Correction”.

Having too little light is as bad as having too much light. Shutting off the office or room lighting while looking at a digital device has its own problems. In dimly lit surroundings the eyes now do not know whether to light adapt to the screen or dark adapt to the surrounding area. 

The general rule with lighting in a computer or digital environment is that you do not want the surrounding lighting to be more than three times brighter or three times dimmer than your device. But without running for a light meter, the easier way to state this is to have the surrounding lighting be about equal to the brightness of the screen. In this way, not only is glare lessened but it also allows the eyes to adapt to the available lighting whether looking at the screen or the other areas of the room. 

Seating and Viewing Distance-  Your posture while working on a computer or digital device can mean a lot when it comes to your comfort and efficiency.

The advantage of most hand held devices and laptops is that they can be positioned to different locations depending upon your posture. With desktop computers, the device usually cannot be changed in it’s position, so you must be the one that changes. The advantage of having a desktop monitor is that it give you more “real estate” to be able to view more information. However, leaning forward or back changes not only your posture but changes the distance from you to your desktop device. This will change the focusing demand on your eyes (covered in another section) but also changes your neck, head and back muscle tension.

Unlike what your mother or grandmother said, “sit up straight” is not the best posture for computer use. In doing so you are actually placing most of your weight in front of your spine and must use muscle power to maintain this 90 degree posture. In actuality, leaning slightly back, against the seat back rest is the best posture. In this way, you have your weight centered and are using the seat itself to relieve some of the muscle strain. 

We all know how easy it is to be “sucked in” to the screen, that is, leaning forward. This is due to the fact that getting closer to an object, or the screen in this case, makes things larger, a desired effect. 

In general, the screen should be about palm to fingertip distance away, with your arm outstretched for a desktop or laptop computer. This reduces the amount of focusing needed by your eyes in order to see the screen clearly. If the screen is not clear at this distance, then the font must be enlarged until it is clear, provided that you are wearing the correct eyeglass or contact lens prescription, if any. Do not move the screen closer. Again, this increases the amount of focusing your eyes must exert and therefore increases eye strain.

For cell phones and tablets, the angle of view can vary greatly, given that these devices are easily moved up, down and to the sides. However, to determine the proper distance to use these, there is a little trick that will help, and will always be with you. Simply make a fist with one hand and place it on your chin. Then extend your elbow out. This is about the proper minimum distance to hold both cell phones and tablets While certainly not exact, it provides you with constant feedback (since your arm is attached to you!) as to the proper working distance. Again, the closer you have the digital device to your eyes, the harder it is to keep and maintain focusing.