Do LCD monitors affect vision?

[Fog Dogg]

wow u know alot about this stuff, anyways, i changed it to 70hz,  iwas at 60 in the beginning :| can u believe it? i was used to it from so long anyways, now im on 70 Hz...on 800x600 res...i also heard about the color quality? i heard u shoulden't have it on 32 bit if u dont play games, etc and it hurts ur eyes? does it?

edit: i gotta get a lcd now ;( any recommendations for a cheap one? i have only about $300 :(]

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Ya, after awhile you do get used to it; I'm used to 75hz, but after being on a labtop with an LCD I can come back and the flicker really bothers me until I get used to it again.

About the colour, the visable difference isn't [i[too[/i] much, so if 16bit doesn't bother you, I don't see why 32bit would.

You plan to buy a $300 LCD? Do you play games?

[TaylorTAP]

Refresh rate: for gaming, your display needs to be capable of updating at least 60 times/second.  Typical (cheap) LCD displays with a 25ms "response time" are only capable of updating 40 times/second.  Therefore, fast moving objects on the screen tear, and leave slight trails (blur).  You will need to get a monitor with a 16ms response time or lower if you are into gaming.  16ms = 62.5Hz refresh rate.  Even better is 12ms, which updates ~83 times/second.  That is in the range of a typical CRT (75-85Hz.)  Usually 85Hz or higher is preferred for gaming, depending on the capabilities of the monitor.

Brightness and Contrast Ratio: an LCD cannot match the light output or contrast ratio of a CRT--at least not yet.  An LCD display cannot render true black.  That is a side-effect of the technology used.  You will see LCDs listed with "Contrast Ratio" specs of 250:1, or 400:1, or 700:1.  The higher the better.  Basically a 500:1 ratio means that the brightest spot on the monitor (100% white) is 500x brigher than the darkest spot (100% black.)  CRT displays CAN show absolute black, and so the contrast ratio between black and white is infinite.  The result of this is that you can only get the true range of shadow detail on a CRT device.  This is true for televisions as well: LCD- or DLP-based tvs, which are all the rage nowadays, cannot render the shadow detail that a CRT-based tv can.

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Ok you are somewhat right but not 100% about this. LCDs can be just fine for games. You are correct that a speedier response time is required but 16ms is way more than you would ever need to not see trailers. Most newer LCDs are perfectly fine for games. It was the first way of cheap LCDs where this was a problem. I have a Samsung LCD that is just VGA and I have never seen 1 trailer on my screen. Also, saying that your monitor needs to refresh 60 times/second is ludacris. Compare this to frame rate of your games. 60 times/second is almost twice faster than the eye can see. Anything over 35fps the eye can't see. That's why your looking to get at least 35fps on your games to get a fluid motion.

Also, regarding your second paragraph saying that LCD's can't project absolute black is false, and you even contradict yourself in another post.

The screen is broken up into a grid of tiny pixels with red/blue/green filters above them. A light shines continuously at the screen, and tiny transistors control the alignment of the liquid crystals in order to let light through or not.

If you've ever taken a physics class, lack of light will create black. If you let no light through the pixel it will create black.

Also, a big flaw in CRTs compared to LCDs is burn-in. I've personally had an experience with burn in. A matter a fact it was my 21-inch Trinitron that ended up getting the check signal when my monitor would go to sleep. After a few months of that showing up when my monitor would go to sleep I had a perminate view of RGB examples on my screen. Oh well, I didn't pay for that monitor my company did but it was still pretty darn expensive.

I'm the network admin for a school of about 2,500 students and I only purchase LCDs. LCDs save huge amounts of power, don't emit heat or radiation. You can see what kind of power/radiation an object emits by getting ahold of 1 of these guys

. It is used in telecom & data to find which wire is which (very useful). It will also transmit DB if you hold it up to a monitor, cell phone, flourscent lighting, or power socket. If you hold it up to a CRT you'll get a nice loud buzz and if you hold it up to a LCD you hear nothing. Scarily, if you hold it up to a GSM phone (or my MPX200) you'll get a nice high pitch tone which sorta scares me (I'm gonna sue the crap outta Motorola if I get a brain tumor).

If your looking for a good LCD, Dell has their 15' for like 250$ right now and it has DVI and VGA ports which is a very good deal for a 15'. Personally, I won't work on anything under a 17' but actually I have dual 19's at work and I only use laptops at home.

Good luck!

[thollian]

keep my CRT @ 85hz....anything less, gives me a headache, and hurts my eyes...

[filter04]

85hz is optimal i read. and despite what some say 16 or 12ms is better for games than 25ms. ;)

[+s55 Subscriber¹]

somehow i dont belive it. playing on a samsung 25ms lcd after my crt was horrible the first few minutes. all blurry. you do however adjust very quickly and dont seem to notice it anymore - which is what happend to you

- honestly i've never seen any gohsting... its either very slight and i've never noticed it or i need my eyes checked... i've only ever seen it on my fathers crappy tfts with (i think its around 40ms on them - was really annoying)

[Jelly2003]

There is no conclusive evidence that any VDU - TV, CRT, LCD, affects eyesight in any way.

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You honestly can't expect anybody to believe that.

The evidence speaks for itself, lets consider the amount of computer users who have glasses. I think most people here would agree that geeks seem to wear glasses more then athletes.

The most important thing that any heavy computer user should do is get high quality gear whenever you can. The better, and more clear the screen image, the less strain on your eyes.

I work at a computer a lot, when I used to use a CRT, I'd suffer horrible headaches, and blurred vision (I wear glasses, so i mean blurrier then normal). When I switched to LCD the headaches stopped, and my vision improved.

Thats why I think LCD's are better then CRT's in that respect.

Staring at an LCD screen all day for hours on end without a rest WILL damage your eyes. In much the same way as staring constantly at a book, or any other close up object will damage your eyes.

Apparently they have discovered why you need to look at things in the distance. Its all to do with where the light focuses on your eyes.

At the back of your eye, inside your retina (the part that processes light) you have a small indent filled with very sensitive retinal receivers. You use this area for detailed vision (reading, etc). Then around the outside you have less sensitive receivers that you use as your peripheral vision, where you cant read, etc.

When you focus on close up objects, you are stimulating the sensitive area, but you are starving the rest of your retina. As a result the rest of your retina becomes jellous and actually forces your eye to grow.

Your eye grows, yet your lens doesn't grow. Because your eye has changed, your lens is designed for how your eye originally was, it doesnt focus the light onto your retina properly anymore, and you end up with blurred vision.

You can try and avoid this by taking brakes every few hours, during the brake, look at distant objects. This apparently stimulates your peripheral vision, which means that it doesn't get jellous and cause your eye to grow.

So there you have it, they why you should take a brake every few hours and not stare at close up objects for extended periods of time.

(I got that info from Dr Karl's show on Triple J, and I am goign to try and find a URL to back up what I just said)

[xxpor]

hey how do u change ur monitors refresh rate? if u cant..lol whats the 80Hz etc about? and on a 15" 800x600 how much Hz should be safe?

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why are you running at 800x600 :blink: anything around 80hz should be good

[DWk]

It's not about being safe or not.... it's whether your monitor can hold it or not.... I'm at 1280x1024 @ 75hz on my 17", on 1024x768 I can do 85hz, and so on.....

[Apollo]

why are you running at 800x600 :blink: anything around 80hz should be good

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maybe he has a 15 inch and bad eyes like me.

when i had a crt and was running 800x600 i had it on 100hz, and it still gave me headaches from time to time.

now with my lcd i don't remeber ever having a headache from it.