wow! so it is a hypo symptom. I wasn't sure. Mine isn't as dark but exactly in the same place, but more of a light orangey colour.
I wonder what actually causes it. A deficiency caused by the hypo? I have short eyebrows too which i know is a common hypo symptom.
I suspected it was to do with the hypo. It is a bit of a relief to know i'm not the only one with it.
The condition you are referring to is called Xanthelasma palpebra, and are lipid deposits in the skin. It can occur with several conditions including hypothyroidism and liver disorders.