There might be a slight difference in your eyes as one sees brighter than the other, and that's completely normal. It's about the biology of the receptors in the back of your eye and then the neural pathways that make sense of them.  Slight differences in any one of those areas can cause a tiny difference in color perception. But some medical conditions can bring a sudden change in color perception in one eye. If you see a vast difference in your eyesight, it's time to consult a doctor.