Red doesnt always get grayed out. It did gray out for me with my first case of ON (left eye), but apparently my second case of ON (right eye) has done some other weirdness.

In the second case of ON, red looked a lot lighter than it should have. Not as vivid as it should have been. My opthalmologist said that he bet if I had an MRI the optic nerve would be showing an obvious case of ON in the right side. (not always true, I had a flaming case of ON in the left eye the year before and the MRI didnt see it)