Colour Blindness

Inability or reduced ability to see colours/colour differences under normal light conditions.

About 8% of men and 0.4% of women suffer.

Most common in red-green area.

Complete colour blindness resulting in only black & white affects only 0.00001% of both genders.

Mostly an inconvenience. Can be restrictive, i.e. aircraft pilots need perfect colour vision.

Consider colour blindness when defining colour scheme for web sites, especially text on background.