I used to drink several cans of Diet Dr.Peper every morning. 3 or 4 a day.
I started to get dark circiles under my eyes and my eyes would itch. I tried drinking more water and cutting out beer. Nothing worked till I cut out the diet pop. It took several weeks but the problems started to go away.
Since then I have tried five times to start drinking it again and every time the problems return. They return much faster than they go away.