I have tried out a couple of things and come to the following conclusions.
1) Standard eyes - too manga-ish.
2) Suggestion of eyebrow - this looked a bit odd to my eye as to make it visible it had to be quite far down on the face and didn't look right. I think this maybe an issue with the fact the bearskin comes down quite low over the eyes than anything else.
3) Black dot - pictured above, this seems to work as it suggests without being too realistic. I might try it again with brown or dark blue. We shall see.