I have had this problem for years and it's so frustrating. It's my left eye that constantly get's heavy and I can feel discharge there and it's always visably noticeable throughout the day (my right eye is fine).
It's always just in the corner of my left eye (a white discharge like sleep just hasnt been wiped out properly).
It's very embarassing and makes me self conscious (avoiding going out).
I've used all sorts of eye drops and tried no drops as well. The eye specialist said it's a mixture of allergies and dry eyes and prescribed pathanol and non preservative eye drops. However this hasn't helped at all.