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Ergovera's Ergo Savvy Newsletter )

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 We help protect people, your company's most valuable asset February 2003 

In This Issue
Researchers finally agree on monitor placement
Research: Mid-height best for monitor placement
New: Sitting for health class
Credits and notices

Published by Ergovera Ergonomic Consulting to help you keep up on ergonomic innovations, so you can protect your employees and increase their productivity. Please pass it on to your colleagues and friends.

Recently, after having laser work done on my eyes, I experienced eyestrain while viewing my VDT monitor. I began to wonder about the monitor's height and my distance from it (i.e., I felt too close). When I changed to smaller casters for my office chair, in order to protect the wood floor, it lowered my sitting height, effectively raising my monitor and my chin as I extended my neck.

Moving my monitor lower and slightly farther away immediately decreased eyestrain and repositioned my head and neck to a more comfortable posture.

As I began to research the topic in the literature, I found disagreement regarding optimal monitor placement. However, the newer research seems to have greater agreement. The variation in recommended monitor height or viewing angle (as is more frequently studied) goes from eye-level (0°) to mid-level, (-15° or - 17.5° depending on the study), to a low level of -35° or -40°.

The studies that support the extremely low monitor position have the monitor submerged below the desk surface. They claim that their findings indicate an increase in blink time, more frequent body movements, and a variety of neck positions.

The recent studies I summarize disagree with the extremely low monitor position. They all agree on a mid-level or somewhat higher position for the monitor. In addition they found:

  • Head/neck position was best at a mid-level (-15° or -17.5°).
  • Decreased muscle activity for the majority of upper back and neck muscles was found with the mid-level position.
  • Individual preferences reflected the benefits of the above findings, with the majority of subjects preferring a mid-level or slightly higher monitor placement.
  • Monitors positioned at eye-level are associated with a slight decrease in performance.

So, encourage your employees to assess their monitor position carefully and educate them on recent research. If there are special conditions (such as bifocals, work tasks or workstation design issues), optimal placement may vary even more, and some employees may need their monitor lower than the recommended mid-level or slightly higher position.

Have a safe day,

Deidre Rogers, RN, MS, CAE

A study by Turville et al. comparing viewing angles of - 15° (mid-height) and -40° (low height) in 10 subjects found no significant difference in blink rate between the two positions as previous research had found. Nor did they find an increase in body movements with the lower position as a previous study found. Rather, they found that the 40° position led to longer static deviated neck posture. They found substantially greater head tilt posture with the 40° position and greater muscle activity except in the left Trapezius muscle. Most subjects preferred the mid-height position. This study used 14" monitors only (i.e., not the larger 17 -19" monitors more common today).

Another study, by Sommerich et al., found that head and neck position as well as overall muscle activity was best at the -17.5° position (mid-height). They found a slight decrease in performance when the monitor was at eye level (0°). These researchers also studied the difference between two sizes of monitors - 14" and 19". They did not find any substantial differences between the two sizes used. The researchers studied 8 touch typists and 8 non- touch typists. They found that non-touch typists displayed greater muscle activity than the touch typists.

A field study (Psihogios et al.) evaluated the eye-level (0°) position and the mid-level (-17.5°) position in 20 subjects who used 17-19" monitors. They found results similar to the previous two controlled studies with the subjective preference greatest for the mid-level and eye-level monitor positions. They concluded that eyestrain was greater for their subjects when working with a monitor located near and high. Surprisingly, they did not find any pattern associated with the presence, absence, or location of an office window.

References

Turville, K., Psihogios, J., Ulmer, T., & Mirka, G. (1998). The effects of video display terminal height on the operator: a comparison of the 15° and 40° recommendations. Applied Ergonomics, 29, (4), 239-246.

Sommerich, C., Joines, S., & Psihogios, P. (2001). Effects of computer monitor viewing angle and related factors on strain, performance, and preference outcomes. Human Factors, 43, (1), 39-55.

Psihogios, J., Sommerich, C., Mirka, G., & Moon, S. (2001). A field evaluation of monitor placement effects in VDT users. Applied Ergonomics, 32, (4), 313- 325.


Want to get your employees to sit up and take responsibility for their posture? Ergovera's new Sitting Training will help eliminate hunchback, sway back, and "chicken neck" postures.

Ergovera's Sitting Training covers:

  • Demystifying Neutral Spine Posture.
  • Utilizing that Ergo Chair.
  • Easy Body Awareness Techniques.
  • Secrets to a Flexible Spine.

Call Deidre at 831.335.8448 or send her a message now for more info about the class, rates and dates we could do the workshop at your site.


Copyright © 2003, Deidre Rogers and Ergovera Ergonomic Consulting. All rights reserved. Reuse in any form must be requested and granted in writing.





  •      email: drogers@ergovera.com
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