One of my engineer patients just came into the office with an
interesting problem.  All the curved screen crt monitors at his office
are blurry to him.
However, flat screen crt monitors as well as laptops and LCD monitors are clear.
Why?
thanks
Fred Bresler

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Request for Question Clarification by techtor-ga on 19 Feb 2004 10:14 PST

Drfred,
Just a hunch, in case the monitors are the ones with the problem. See
if there's anything in the office creating a large magnetic field in
that office, or if there are any magnetic trinkets (like paper
holders) near the monitors. Blurry monitors can be the result of
magnetic fields placed near them. Perhaps unshielded 
subwoofers/speakers are being placed near the monitors.

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Request for Question Clarification by techtor-ga on 19 Feb 2004 10:35 PST

May I add, only CRT monitors are distorted by magnetism. LCD monitors
I believe are not.

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Clarification of Question by drfred-ga on 19 Feb 2004 11:10 PST

He also has flat screen crt monitors that do not cause the blurriness.
It is only the regular curved fronts that do this on all the crts in
his office.  He also just got a new Dell system at home that came with
a curved
crt and he had to return it for a lcd monitor.
Fred

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Clarification of Question by drfred-ga on 19 Feb 2004 11:14 PST

He is the only one that has this blurriness.  All the other engineers have
no difficulties at all with any of the monitors.  I will ask him if he
is a self generator of rf when he comes back.
Fred

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Clarification of Question by drfred-ga on 19 Feb 2004 13:52 PST

Well-I am an eye doc and his accom is fine as is his near point of
convergence, etc.  I don't think that either of them would only affect
one type of monitor and not the other. thanks.
Fred

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Request for Question Clarification by feilong-ga on 19 Feb 2004 17:43 PST

Hi Drfred,

Could you plese ask your patient to change the video adapter Refresh
rate of his monitor to Adapter default or 60 Hz and see if that solves
the problem?

On some monitors, especially CRTs, when the refresh rate is set to
Optimal (about 85 to 90 Hz), the screen becomes blurry. People who are
used to this kind of refresh rate can't seem to notice the diffence
when looking at a monitor with lower refresh rate. Perhaps your
patient's eyes is just sensitive to this diference and that may be the
reason why "He is the only one that has this blurriness. All the other
engineers have no difficulties at all with any of the monitors."

Please advise if this is the case.

Best regards,
Feilong

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Clarification of Question by drfred-ga on 20 Feb 2004 06:59 PST

Feilong-great thought!  When he gets back to work on Monday I will call him
and see if that does the trick and I will post back to you.
Thanks
Fred

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Request for Question Clarification by feilong-ga on 20 Feb 2004 07:24 PST

Thanks Drfred. In addition, it may also help if your patient wipe the
monitor clean. I'll wait for your reply. Thanks again.

Best regards,
Feilong

Dr Fred

Is your patient the only one in the office who sees the monitors in this way?

Dr Fred

Maybe your patient carries something on his person that is causing the interference?

Am I right in thinking that crts with curved fronts represent an older
type technology?

Maybe the flat screen type have better screening?

Hi drfred-ga,

  Here are my comments on your patients vision problem:
I am ruling out the issue is with any personal thing carried by your
patient, since he could see a flat screen CRT clearly.  Also the
interference will be prominent enough to show what causes it.
The primary difference between a flat and curved monitor is the
nature of th surface. In order to see both the surfaces clearly,
the depth of vision is adjusted automatically by the eye by controlling
the aperture of the pupil. This is also refered to as the "power of
accomodation". Unless your patient could clearly see using a single
eye, he might be losing the strength in his eye muscles that control
the power of accomodation. A best advice is to get an appointment with
an eye specialist, or to undergo exercises that could help identify/improve this
(eg. holding a pencil close to the eye, and then keep switching focus
alternatively towards a distant object). Eating lot of spinach,carrots
and taking other supplements(lutein,bilberry,vitaminA+E,CoQ10) while
cutting down on caffiene intake will help. Physical theraphy such as 
closing the eyes and looking at the sun and frequent application of 
cold water/massage around eye will improve the strength of the eye 
muscles by improving  blood circulation. One other possibility is that
your patient might be suffering from initial stages of an eye disease
such as cataract(Being a diabetic increases the probability).

Regards
ldavinci-ga

Hi drfred-ga,

   Since you are an eye doctor, I am ruling out the possibility of any
eye related issues.  How/when did your patient identify his problem?
Does this problem develop recently(as he was using a curved CRT)? or
Did he notice it when he started using a curved CRT recently?
I suspect it could be an issue with his brain getting trained over a 
flat screen CRT/LCD display all the time, and did not have enough time 
to retrain the vision on the curved CRT's. Could you confirm, if he
sees a blurry image on any curved illuminated surface resembling a monitor,
or just the CRT monitors?

Just a shot in the wild!.

Regards
ldavinci-ga

Hi Dr Fred,

  I hope you find the following links useful in resolving your patients
problem:
http://arapaho.nsuok.edu/~salmonto/CVS.pdf
http://www.pocket-stress.com/PDF/Goodbye%20to%20the%20VDU%20Headache.pdf
http://www.nap.edu/openbook/0309033888/html/66-110.htm
http://www.ifado.de/vision/contents/jaschinski/eyetestpc/eye_test_pc_english.htm


Regards
ldavinci-ga

Yes, refresh rate is important. 

I'm the only one in my family who can "see" the flickering of a
monitor set on a too low refresh-rate. The difference to me, when it's
adjusted correctly, is like night and day.

Also, with regard to the flat vs curved screen ..I also notice the
"bow" of the curved screen much more than everyone else when I switch
between monitors. When I go on the kids' computer I find myself
constantly adjusting their curved monitor settings to make it more
comfortable and "flat" looking.

Finally, I guess I'd consider the distance. Maybe for some reason he
is sitting closer or farther from the flat screen? Or a glare is
hitting the curved screens differently?

Interesting dilemma. Be sure to let us know the answer if you figure it out. 

-K~

He just got back to me today.  He had already adjusted the refresh
rate from 60 to 85 and in between previously and that did not help. 
He also reminded me that
he has the same trouble at home with televisions, but not flat screen
tvs or LCD tv's if that helps.  He tells me that there are a lot of
upset engineers in his office as he made changes to all of their
screens without success.
Fred