Refresh rate on an an LCD monitor?

[Terry Pinnell]

I'm trying to discover whether the serious headaches I'm getting from
10-12 hours PC usage per day are caused entirely by eyestrain from
this 24" Iiyama LCD (model E2403WS). Yet I didn't get such a problem
with my previous 19" CRT.

There seems no way to change the refresh rate (60 Hz) of this Iiyama
monitor. But what does 'refresh rate' mean for an LCD/TFT screen
anyway? I thought that applied only to CRT monitors?

It's a tad off-topic, but any advice on screen position, height,
posture, etc would also be appreciated please.

BTW, in case it's relevant, these headaches are almost always on one
side (my left), and I'm wondering if somehow I'm using the left eye
significantly more than the right since I got this widescreen
(January)? For instance, as I type this in my newsreader
program, Agent, the text occupies less than a third of the screen, so
I'm obviously looking leftwards. But then *most* applications are
pretty evenly spread, so that wouldn't seem likely.

I do appreciate that I'm probably my own worst enemy here! But I'd
find it very hard to drastically reduce my PC usage...

 

[Bob Myers]

There seems no way to change the refresh rate (60 Hz) of this Iiyama
monitor. But what does 'refresh rate' mean for an LCD/TFT screen
anyway? I thought that applied only to CRT monitors?

"Refresh rate" means exactly the same thing for LCDs that
it does for CRTs - the number of times per second a new
frame of information is "drawn" on the screen. The major
difference in the LCD is that, very much unlike the CRT,
the image is relatively stable after being "drawn" and does not
appreciably fade between re-writes. Almost all LCDs in
desktop monitors are refreshed at or very near a 60 Hz rate,
regardless of the input video timing. (If a different input
frame rate is used, the monitor's "front end" circuitry performs
a frame-rate conversion in order to drive the panel itself at
its desired timing. As this may result in some visible motion
artifacts, it is recommended that you simply use the correct
frame rate for the input video in the first place.)

It's a tad off-topic, but any advice on screen position, height,
posture, etc would also be appreciated please.

There are several things that could be causing headaches
besides the refresh rate - and in fact, refresh rate with an LCD
is just about the bottom of the list. LCDs simply do not suffer
from the "flicker" phenomenon that CRTs were prone to. But
with that factor aside, you could still be suffering from the effects
of poor posture/ergonomics, screen glare or other ambient lighting
problems, or simple eyestrain. Doing ANY sort of close-up detail
work for an extended period of time can cause eyestrain and
headaches, and you should for that reason alone take regular
breaks.

One other possible factor - do you wear glasses, and specifically
bifocals or "progressive" ("lineless" bifocal) lenses? If so, it may
be that you're forcing yourself to look through the glasses in a
very uncomfortable head position, simply to keep the screen in
focus. Changing the screen height/angle, and/or getting a pair
of "computer" glasses (in which the "comfortable screen-distance
reading" area extends much higher than in conventional bifocals)
might help here.

Bob M.

 

[Rotten Ronny]

I'm trying to discover whether the serious headaches I'm getting from
10-12 hours PC usage per day are caused entirely by eyestrain from
this 24" Iiyama LCD (model E2403WS). Yet I didn't get such a problem
with my previous 19" CRT.

LCDs use fluorescent bulbs for the backlighting and I expect that is what
your issue is and not the refresh rate. Fluorescent lighting causes some
people to get headaches. You can lower the chance of headaches by adjusting
the contrast and brightness levels. All LCDs I have seen are too bright at
their default settings. My Samsung LCD has presets and I found their text
setting is exactly the same as my custom setting when I used a grayscale.
Use a grayscale on a website and adjust brightness so darkest black is black
and all the other dark toned blocks are visible, adjust the contrast to the
white blocks so pure white just turns white and all the other light toned
blocks are visible. Most LCDs set white so that it burns your eyes out when
viewing a website with a white background.

 

[Terry Pinnell]

LCDs use fluorescent bulbs for the backlighting and I expect that is what
your issue is and not the refresh rate. Fluorescent lighting causes some
people to get headaches. You can lower the chance of headaches by adjusting
the contrast and brightness levels. All LCDs I have seen are too bright at
their default settings. My Samsung LCD has presets and I found their text
setting is exactly the same as my custom setting when I used a grayscale.
Use a grayscale on a website and adjust brightness so darkest black is black
and all the other dark toned blocks are visible, adjust the contrast to the
white blocks so pure white just turns white and all the other light toned
blocks are visible. Most LCDs set white so that it burns your eyes out when
viewing a website with a white background.

Thanks both, I'll follow up those suggestions.