I was wounded and everything gone redish. After a while enemy come to finish me off and I respawned with same redish screen. Couldnt get rid of it even with ALT-TABing. Ive managed to fix it by selecting some of advanced graphics options which needed to reload textures or something like that. I think I put shadows on "very high" and engine needed to recalculate and got back to normal vision. As long as I can remember it was one of the standard missions that comes with Arma so "First Aid" was probably included.
My system specs:
Athlon64 X2 5600
3 GB DDR2 800 MHz
nVidia 9600GT 512 DDR3
Seagate Baracuda 320 GB SATA2
Windows XP Pro SP3
