What Is The Darkness In My Eye Duct To Tear Duct?

Hi Doc, I have darkness that has appeared at my eye ducts (both eyes), going from lower eye on the bridge of my nose to slightly above my tear ducts. I am a 55 yo male, no smoker, in good physical shape, no history of illness. While I know I do not get enough rest (work requires on/off cycles with 4 to 5 hours rest in between), I am surprised at the darkness, and where it is (no bags under the eyes). What could this be? Is it temporary or a symptom of something else. Thanks for your help.