Hello, over the past few days or so I have had a little discomfort in my right eye in the right corner where they eyelids meet. It almost feels like I have an eyelash there rubbing but from what I can see there is nothing there. If I was to go to sleep in the morning it will be fine but towards the end of the day it comes back, it is not persistent and will sometimes go away for an hour or so. It is not painful, just irritating. What could this be?