Just relaying my own experience, even though it seems different than
yours...
I don't know if this will help you since I have not used that model, but
when I first switched to LCD's not that long ago, there was a bit of a
transition period that my eyes went through for the first few days of moving
from a CRT to an LCD. At first, LCD's seemed way too bright for me and I
found myself turning the brightness and contrast way down in hopes of
matching the brightness of my CRT's. After trying that for a little bit, it
seemed to me that my eyes were somewhat strained from trying to match the
brightness and contrast. I then went in the other direction and made my
LCD's brighter than I've ever used on a CRT. It did take a little getting
used to at first, but after that, it's been very good. However, seeing that
you have your Samsung set to 50% brightness, I would assume it's already way
brighter than your old CRT. Maybe try lowering it. I guess everyone has
different eyes.
This might be a bit of a long shot, but I have to wonder if the response
time of your LCD might be a bit of an issue. The LCD that I'm using on my
Internet computer here is a 15" model with a 25ms response time and analog
plug only. Even when scrolling text on the screen, I can see slight
ghosting. It's not really an issue for me, but it could be for you. My
other LCD on my main computer is a 16ms 17" model with a DVI connection and
it's definitely an improvement. That's not to say that my 25ms LCD is bad
by any means, but I know that large LCD's like what you have are almost
impossible to get with response times of 25ms (at least to my current
knowledge).
I wear glasses and have a fairly strong prescription. Without my glasses, I
suffer from pretty bad astigmatism, along with near-sightedness. Reading a
monitor or newspaper from more than 10 or 12 inches away from my face is
practically impossible for me without my glasses.