Over the past 6 months or so I've been slowly developing these dark purple veins under my eyes. I've got one under my left eye that goes from bottom to top, and now I see two more starting to appear under my right eye. I think they might be called spider veins, but I'm not toally sure if that's what it is.

So my question is, what's causing these? Granted I have a very erratic sleep schedule so I usually don't get what you would call a good night's sleep, but that's how it's been for a while and these veins are a recent occurrence. Consequently I've ruled out sleep as the cause, but I guess I should leave the diagnosis to you guys.