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Ergonomic Tips: Vision and Monitors

1. Vision-related complaints are the most common complaints associated with computer work.

2. What are the symptoms associated with eyestrain? Headaches, difficulties in color perception (When you look away from the colored screen to another colored object, do you perceive the color correctly?), focusing problems, and double vision.

3. If you can see flicker on your screen (characters on the screen do not appear to be continuous), you may need a screen with a higher refresh rate.

4. Ergonomic Terms. The image on your VDT screen is not a constant image, although it appears to be a constant image. The screen image is being continually repainted or refreshed by an electron gun in the VDT. Refresh rate refers to how often the screen electronically "re-paints" itself. The higher the refresh rate, the less likely flicker is to be problem. Typical refresh rates for VDTs are in the range of 60-80 cycles per second (cps or Hz). This means that the screen repaints itself 60 to 80 times each second!

5. Ergonomic Terms. A pixel is one of the individual units that make up a VDT screen. Pixel is short for "picture element". The total number of pixels making up the VDT screen defines the resolution of the screen.

6. Screen resolution (pixels per unit area on the screen) appears to be the most important screen characteristic when determining viewing comfort. Higher resolution equals increased comfort.

7. Select a monitor's resolution based on the tasks you will be performing. If you are performing word processing and spreadsheet activities, you want a monitor with a 640x480 resolution. If you are working in a Windows environment with graphics, you want a monitor with a 1024x768 resolution. If you are working in a CAD environment, you want a 1280x1024 resolution.

8. Remember to adjust brightness and contrast on your screen, especially as lighting conditions change in the work place (e.g., sunny versus cloudy day).

9. Tilting Your Monitor. Draw an imaginary line from your eye to the center of the screen. Tilt the monitor so that the angle of the screen relative to the imaginary line is nearly perpendicular (90 degrees). This will enhance viewing of the screen by avoiding parallax effects.

10. Glare on the computer screen is one of the most common complaints among computer users. There are three ways to minimize glare on the screen. You can eliminate the source of the glare. You can reposition the monitor so it is not in-line with the source of the glare. Or you can place an anti-glare filter on the screen. Consider these control strategies a hierarchy (i.e., try to eliminate the source of glare before using an anti-glare filter).

11. You can reduce glare by changing the polarity of the screen. A reverse polarity screen (dark characters on a light background) is more resistant to glare effects than a standard polarity screen (light characters on a dark background). Many software packages allow you to select the polarity of the screen.

12. You can eliminate the source of glare by turning off lights in the work place. Remember to use task lighting for things like source documents if you reduce the overall lighting levels.

13. Change lighting levels during the course of the work day. You may need your overhead lights on in the morning, but you might want to turn them off in the afternoon. Be aware of when glare occurs, and respond appropriately.

14. Use full-spectrum lighting to reduce glare. Full-spectrum lighting emits light along a wider spectrum of the full visible light range. One of it's benefits is reducing glare on screens.

15. Closing blinds or drawing curtains at windows is a good way to eliminate a source of glare on screens.

16. Tinting windows is a good way to reduce the glare coming through windows.

17. To reduce glare, move the computer so that the source of the glare does not directly strike the screen. For example, keep light sources at a 90 degree angle to the screen.

18. To reduce glare, tilt the screen so that the source of the glare does not directly strike the screen. But do not tilt the screen forward past vertical (it can increase strain on the neck).

19. If you need a glare filter for your monitor, select a circular polarizing filter made of specially-treated glass, versus a mesh filter. Polarizing filters usually produce a clearer view of the screen.

20. Clean both the screen and the glare filter regularly to reduce glare and provide a clearer picture.

21. Do not use a glare filter unless glare is an issue. A glare filter does not help viewing the screen, it just reduces glare on the screen.

22. Do not use sunglasses as a means to reduce glare. All this does is make the screen darker, it does not make the glare go away.

23. Avoid placing a hood over the screen to reduce (block) glare. It is usually difficult to avoid shadows on the screen using this method.

24. Glare can come from sources other than the monitor. Avoid shiny, reflective surfaces in your viewing area that might end up being glare sources.

25. If you have work surfaces that are highly reflective or shiny, reducing the overall lighting levels can accommodate for this.

26. Avoid positioning your monitor so bright lights (e.g., a window) are directly behind the monitor. This can end up being a source of glare. In general, avoid high- luminance sources in the peripheral field of view.

27. Many software packages allow to select the colors you display on the screen. The visual system has to work harder as more and more colors are added to the screen. Try to keep colors on the screen at a minimum.

28. Instead of using colors on the screen to highlight different areas, use shading or other monochromatic approaches that are easier on the visual system.

29. When selecting colors for the computer screen, always select colors with a high contrast. For example, Blue/Yellow is a color combination with inherent high contrast.

30. When selecting colors for the computer screen, avoid extreme color combinations such as Red/Blue or Purple/Yellow.

31. When selecting colors for the computer screen, avoid colors in the extreme of the color spectrum, such as blue-violet and red. The eye is least receptive to these colors.

32. When selecting colors for the computer screen, do not use white on yellow. It does not provide sufficient color contrast.

33. When selecting colors for the computer screen, do not use yellow on green. These colors can produce a perception of a "vibrating" effect that can be annoying.

34. When considering color to use on a computer screen, do not forget that about 10% of the population is color blind.

35. The first thing you should do if you experience visual fatigue or strain at work is to have your eyes examined.

36. It is reported that over 30% of the population is either in need of prescription glasses, or in need of a new prescription.

37. Have your eyes examined at least annually, and preferably every 6 months.

38. Tell your eye doctor that you work on a computer, so the doctor can prescribe glasses with the proper focal length for computer use.

39. Prescription computer glasses typically have a depth of focus that covers the distance between screen and keyboard. You may have to switch or remove the glasses for objects outside the depth of focus.

40.Bi-focal wearers who use a computer may want to consider a continuous-curve bi- focal lens (i.e., the bi-focal extends the entire lens surface area).

41. Clean your glasses regularly to avoid eye fatigue.

42. Avoid wearing contact lenses when you work at the computer. Computers emit a dry, static heat that dries out the eyes. Contact lenses tend to dry out the eyes. It's the worst of both worlds.

43. Remember to blink when you are working at the computer. Studies have shown that blinking rates decrease when working at the computer, compared to other visual tasks. Blinking is how the eye lubricates itself, so make a conscious effort to blink.

44. Certain medications (diuretics, antihistamines) can reduce the production of lubricating tears. If experiencing dry eyes at work and taking medication, check with your doctor to see if the medication may be contributing to the dry eyes.

45. Besides remembering to blink more, dry eyes at work can be relieved through eye drops. Select eye drops that are strictly lubricants. Don't get drops containing decongestants or vasoconstrictors.

46. If you have long messages sent to you through the computer (E-mail, etc.), print them out and read them instead of reading them on the screen. Reading printed material tends to be easier on the eyes than reading the same materials on the screen (blink rates being one of the reasons).

47. Constant short-distance viewing (like that required when using a computer) has been associated with myopia (near-sighted vision). Look away from the computer screen occasionally to minimize this risk.

48. While computer use (or other intensive short-distance viewing tasks) may lead to myopia or other visual defects requiring corrective lenses, there is no evidence that using a computer can result in an increased risk of cataracts or retinal damage.

49. Eye Exercises. Take your pen and hold it at arm's length. Focus on the pencil with your eyes. Then slowly move the pen in towards the eyes until the pen gets blurry. Close your eyes and take a deep breath (relax). Move the pen back to arm's length and open your eyes. Repeat 5 times.

50. Eye Exercises. Rest your eyes routinely by focusing on objects at different distances. Look at an object far away (at least 50 feet) for a count of 10, then look at an object close for a count of 10. Repeat this 5 times.

51. Eye Exercises. Close your eyes, and preferably cover your eyes with your hands. Keep them closed for up to 30 seconds. Take several deep breaths to relax while your eyes are closed. Slowly open your eyes.

52. Older workers have specific visual requirements when it comes to computers. Try to avoid highly saturated colors on the screen such as reds, blues, purples.

53. Older workers have specific visual requirements when it comes to computers. Avoid colors with low luminance due to the decreased sensitivity of the eye.

54. Older workers have specific visual requirements when it comes to computers. Avoid the use of blue on the screen, because it is difficult to discriminate.

55. Older workers have specific visual requirements when it comes to computers. Often illumination (lighting) levels will have to be increased for older computer users. Task lighting is preferred in order to provide adequate lighting levels and minimize glare.

Ergonomic Tips:  Introduction
Ergonomic Tips:  For Office Workers
Ergonomic Tips:  Workstation
Ergonomic Tips:  Physical Environment
Ergonomic Tips:  Psychosocial
Ergonomic Tips:  Materials Handling
Ergonomic Tips:  Vision & Monitors
Ergonomic Tips:  Personal Risk Factors

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