I have two pugs, the adult's eyes show bright blue in pictures with a flash. The other show dull green. Very much like a cataract would show on a flash picture. She is a baby. Her first vet appointment is next week. Shows no visual impairment.
it has to do with how the flash light reflects off the retina.
I wonder if the reason the colors reflect differently from one dog to another (just my hypothesis!) is that these dogs have different numbers of rods and cones on their retinas, even though they are the same breed. Tests have shown that some dogs can see in more colors than other (dogs don't see in total black, white and grey as their eyes have both rods and cones, it's suspected their colors are more washed out or grayed out).
So perhaps one of your dogs can see better in color and the other can see better at night. Again, just a theory :)