Is an LED monitor better for eyes than an LCD monitor?
Solution 1:
there are two things which are casually referred to as "LED" monitor
OLED monitors - these are relatively small, as of the current moment, each pixel is lit by a small OLED, usually used on mobile devices only. there are desktop implementation (read: the sony OLED monitor which cost thousands of dollars). these looks better. they have great contrast ratio, good color rendition but are expensive & had a relatively short lifespan (due to the blue OLEDs - these had relatively low efficiency and die off early)
see http://en.wikipedia.org/wiki/Organic_LED#Disadvantages for details.LED-backlight LCDs. there are still two kinds of these things on the market. The cheap kind is white-LED based. The color rendition is not yet on par with good CCFL backlights (e.g. iMac 27" vs dell U2711, the imac uses the white LED backlight and dell U2711 uses CCFL backlight but the dell had a larger gamut (color range)). the RGB LED backlight is very advanced and can give a very large gamut.
in general, looking at monitors does nothing to the health of your eyes, and more importantly, the contrast and brightness settings matters more than the nature of the lighting efficiency. In selecting monitor. First choose LCD panel (if you needed it - IPS panel vs TN panels vs VA panels) then choose backlight (colour range, power use).
To make everything easier to your eye, adjust the brightness of your monitor according to your ambient light level.
Solution 2:
Ok, firstly there aren't any truely LED monitors. What you can buy nowadays is a LED backlight LCD monitor.
On that basis, I don't think there is any difference at all. LED backlight monitors do have a better contrast ratio, but I don't think that they're yet good enough to have a real difference to eyestrain.
Solution 3:
As far as flicker goes, it depends on how the backlight driver works. When I was at a computer store several months ago (late 2010), I examined many of the LED-backlit LCD monitors, and found that almost all of them flickered noticeably when the brightness was turned down to a comfortable level, while my CCFL-backlit LCD has no flicker, even at minimum brightness.
You can easily test a monitor's flicker by waving your finger back and forth in front of the screen while showing a bright image, like solid white. If you see a smooth blur of an afterimage, it's not flickering; if you see lots of distinct after-images of your finger, it's flickering at a low rate and can cause eyestrain.
It's pathetic that LED backlight drivers don't set the flicker rate much higher so it's not visible, since LEDs impose virtually no constraints on the rate. But LED backlighting is still in its growing stages, so give it a few years.