Of late, due to almost 10 years of using PC Monday to Friday, of 8 hours each, I have discovered that my eyesight is not as sharp as it used to be. I just noticed that I have difficulty in seeing small readable materials that are poorly lit especialy at night. It means that for me to be able to read very well at night, I have to put in more light especially directly to the material I need to read. I have similarly linked this short coming to constant use of Computer Monitor, now refer to mostly as Computer Vision Syndrome.
The first thing to note here is that the hazards is more associated to a “habitual” computer user. That’s not to say that the occasional computer user won’t have the hazard, everyone’s level of sensitivity is different No doubt, looking at the monitor for extended periods can cause eyestrain. Eyestrain means different things to different people. It may be experienced as burning, tightness, sharp pains, dull pains, watering, blurring, double vision, headaches, and other sensations depending on the person. Hazards associated with Computer Monitor can include any or all of the following symptoms:
• Temporary myopia, the inability to focus clearly on distant objects for a few minutes to a few hours after using the computer;
• Eyestrain or eye fatigue, a tired, aching heaviness of the eyelids or forehead;
• Blurred vision for near or far objects, and sometimes double vision or after images;
• Dry, irritated or watery eyes;
• Increased sensitivity to light; and
• Headaches, neckaches, backaches and muscle spasms from holding the body in awkward positions to maintain a desirable angle between eyes and screen.
A number of workplace factors can lead to it, chiefly among them includes:
• Poor position in relation to the computer;
• Lighting that produces glare or reflections, fuzzy images or images that are too dim or too bright;
• Failure to blink often enough to moisten the surface of the eyes;
• Use of corrective lenses that are inappropriate for the user’s position and distance from the screen;
• Minor visual defects that might go unnoticed if not exaggerated by intense computer use.
Anit hazard preventive measures should include the following:
• Any windows should be at right angles to the computer screen, rather than behind it or in front of it;
• There should be enough light to read the words on the screen without straining;
• There should be no reflections on the screen from overhead lights, windows or desk lamps;
• The screen contrast should be adequate to produce sharply defined images.
Another hazard is the headache produced by the almost invisible ‘flicker’ of the monitor as the image on screen is refreshed. The solution is to increase the refresh rate of the monitor to at least 75hz. Your monitor driver or control panel should offer you a choice of refresh rates. To find out if your monitor is flickering, pay attention only to the view in your peripheral vision. If you see a faint flicker, or find yourself getting frequent headaches, increase your refresh rate, reduce the contrast on screen, sit further from the screen, and increase the ambient lighting around your workstation.
Standard flourescent lights also flicker and can cause headaches or dizziness. If you can, use reflected light from halogens or daylight-spectrum flourescents – shine the light onto the ceiling or wall, never toward your eyes. Best of all is reflected daylight, but don’t allow glare on the screen.
The position of your head is also important. Your monitor should be placed below the level of your head, and tilted slightly upward, so your gaze is slightly downward, putting your neck in a more natural, relaxed position.
Posted by twinstaiye 
Posted by twinstaiye 
