Well, in the interest of thoroughly exhausting the possibilities, it appears that extraocular photoreception in humans has not been ruled out entirely. A number of animals apparently have demonstrated it (including birds, tadpoles, squid?), including sensitivity through the skin and/or pineal gland as well as sensitivity to color (here’s food for thought). And there was that study a few years back that claimed that you could reset the biological clock in humans by shining light behind the knees. Of course that study’s controversial - but the upshot is it’s not quite patently absurd to suggest that there may be photoreceptors outside the eye.
So if we suppose the woman is some sort of genetic throwback with some vestigal newt-like color-sensitive photoreceptors in her skin or forebrain, who knows? Anything’s possible. Of course photoreception is not the same thing as vision at all, but if the hypothetical extraocular photoreceptors were color-sensitive, and if their action was something that could be consciously sensed, we could hypothesize some means of getting color information into the consciousness via the skin.
About equally likely (i.e. *not *) would be the possibilty of some functioning teratoma - a third eye - somewhere on her body. There are cases of tumors that include fully formed eyes (anybody read the Dark Half? blech). In my quick googling I couldn’t find any cases of functioning eyes and it sounds pretty damn unlikely, but again who knows.
Just so we think of everything before we come to the inevitable conclusion that she’s looking through that little hole between the blindfold and her nose.