I'm not sure if it's an on going problem but here's my advice anyway:
Go to a vet. My degu had the same problem, and once I finally found a vet to examine him his prognosis wasn't too good. His molars were overgrown, and the root of one of the maxillary molars was growing up towards to the orbit causing serious sinusitis - which resulted in the gooey discharge from his eye. They said there wasn't a whole lot they could do for that besides pain management since it results in chronic pain. The day after dentistry was performed he passed away.
I've attached Spaz's x-ray for anyone who wants to see a degu with maloccluded molars and over-grown roots. You can also see his lack of maxillary incisors in the photo.
The same degu had discharge from his eye around 6months ago too and it turned out to be an infection - the vet prescribed drops and the problem was gone within a few days.