Having trouble seeing the number 56

yes, then try adjusting your monitor colour gamma's (red and green). You can do this if you have Adobe Gamma in your computers control panel.

This subject is really interesting. Colour perception is a subjective issue. I myself have supposedly got partial red/green colour blindness. This was determined when I was at primary school when I was tested. I was apparently abnormal when it came to distinguishing red and green colours.

The truth is that I wasn’t abnormal at all, its just that the second rate star 93 million miles away was emitting slightly wrong amounts of red and green light in its colour spectrum.