Eye strain

Discussion in 'Archived Threads 2001-2004' started by Steve_J, Jul 13, 2001.

  1. Steve_J

    Steve_J Extra

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    Lately I have been experiencing eye strain associated with pretty much any material with my 36" Zenith. I have been fiddling with the contrast setting quite a bit and am wondering: normally is it high or low contrast which would cause eye strain? The eye strain, BTW, can lead to headaches sometimes just within minutes of viewing. I'm sitting rather close to the screen for my taste, I'd say about 6 feet from the screen and the crappy quality of the Zenith can't help. What do you guys suggest doing to help? Thanks.
    [Edited last by Steve_J on July 13, 2001 at 02:10 AM]
     
  2. ThomasL

    ThomasL Supporting Actor

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    Steve, besides a trip to the eye doctor [​IMG], I'd guess you should try sitting a little farther away if possible. I work in the computer world so I do know something about eye strain from staring at monitors all day. I suspect that you're close enough so your eyes are detecting the flicker of the interlaced image. While you may not notice it consciously, your eyes are registering it. This leads to eye strain and headaches. Unlike a computer monitor, you can't easily just change your video driver to use a higher refresh rate, so one solution would be to sit farther away from the image if possible.
    Also, I'd guess that both a too low and too high contrast setting may lead to eye fatigue depending on the lighting in your room. Another cause of eye fatigue is when the tv is the only source of light in the room. This causes your eyes to completely focus on the tv light and can lead to eye strain. I believe this is why people try to set up back lighting in their home theater rooms.
    hope this helps,
    --tom
     
  3. Doug_L

    Doug_L Stunt Coordinator

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    I agree with everything ThomasL said.
    You're probably sitting too close.
    Check the contrast and brightness controls with Avia or Video Essentials. Things should improve.
    And never, never watch TV in a completely dark room with a direct-view monitor. The difference in light output from bright scenes to dark scenes can be a real shock to your iris, which will open or close accordingly, and with each change of scene; this, I believe, is the leading cause of eyestrain. I highly recommend using a bias light behind your monitor.
    If you're unfamiliar with the concept, the bias light puts out a small amount of light which is not noticeable during bright scenes, ie: the light output from the TV determines the overall light in the viewing room. During dark scenes, however, when the light output from the TV drops, the light from the bias light keeps the overall light level in the viewing environment at an acceptable level, called X. X is bright enough that your iris will not open too much during the dark scene, but dark enough that you can still see the shadow details on a properly calibrated screen. Also, level X is high enough that your iris will not be shocked into closing quickly when a bright scene comes on.
    Installing the light behind the monitor is also important, because it prevents the glare that in normally associated with ambient, or even directional light, in the viewing environment.
    Not the best explanation (had a rough night), but hopefully clear enough and directionally correct.
     
  4. Steve_J

    Steve_J Extra

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    Thanks for your help. Most of my TV viewing is done with the lights on so that is not the problem. In the past I have achieved a setting messing around with contrast, etc. that has yielded an image that never caused eye strain or hurt. I recently altered this setting because I am well stupid and do not remember it. AVIA doesn't help me calibrate contrast very well because IMHO it isn't clear at all. I am just trying to return to that contrast setting which yields a good result which is why I want to know whether to lower or higher my contrast. Also we have replaced/added a brighter light in our ceiling that was not there so now we have more light output than before. Does this mean I should raise contrast to compensate? Thanks.
     
  5. ThomasL

    ThomasL Supporting Actor

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    Steve, if you've changed the level of lighting in the room, you should recalibrate both brightness and contrast. Setting the contrast on a direct view is one of the harder things to do. The rule that people have stated here and I seem to be comfortable with it is to put contrast at 0, tick it up and keep going until you see the top box change from a grayish-white to what you perceive as white. Then tick it it one notch (or two depending on the scale) just to be sure.
    --tom
     

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