Aging can cause a decrease in retain sensitivity: "Cells in the retina that are responsible for normal color vision decline in sensitivity as we age, causing colors to become less bright and the contrast between different colors to be less noticeable. ... In particular, blue colors may appear faded or "washed out." While there is no treatment for this normal, age-related loss of color perception, you should be aware of this loss if your profession (e.g. artist, seamstress or electrician) requires fine color discrimination."