I have darkened the background colour of all input and reply boxes plus removed the nice little texture image that was overlaid, the result of which is that there is now more contrast in the reply boxes. This was done due to it being mentioned on the forums and also we did receive one direct PM asking if anything could be done to help with the situation.
The last thing I tried to improve was the brightness/visibility of the flashing cursor but that is automatically controlled at the operating system level on your pc's. It is supposed to change it to always be visible and without me implementing some fancy Java programming or making the cursors into images (coloured) then there is nothing more I can do.
Hopefully these small changes are a help though