In a couple, both the man and the wife have normal vision, although their fathers were colourblind and mothers do not have any allele for colourblindness. In their progeny, the probability of colourblind daughters is

Wife is a carrier (X^CX) since her father is colourblind. Man is normal (XY) as he inherits X-chromosome from normal mother.

Offspring of such a couple would be; one carrier daughter(X^CX), one normal daughter(XX), one colourblind son(XCY), and a normal son(XY).

So, the daughters may be carriers or normal but not affected.