Re: Don't blame the user
"Coloured text on a coloured screen; colour-blind user."
It's surprising how this can get overlooked. In my area of forensic science we tended to do a lot of colour matching of fibres in microscopy. My initial boss couldn't do that part of the job, he was colour blind*. About 4 years later when I'd got to the level of doing recruiting my office-mate & I decided we really should screen candidates for colour vision.
*He'd come in via a medical lab-tech background where microscopy tended to use red/blue staining.