It could be, or it could be mood related, or lack of sleep. My eyes change shades of blue. Today they look gray. My allergies are acting up and I am a little short on sleep. Other times I have had friends comment on how bright blue they are.
A person I know has brilliant blue eyes but lately they seem to be a duller blue. Is this a sign of illness?
My wife had the brightest blue eyes. When she was very tired or did not sleep well they would dull.
My wife had Caribbean ocean blue eyes that seemed to fade in color as the day got late. When she was tired or sick they would always get a little less intense in color.