Dry eye syndrome, marked by feelings of grittiness, irritation, and burning as well as difficulty reading for long periods of time, and, even though it seems quite contradictory, excessive tearing or watering of the eyes, is a potentially debilitating condition that requires treatment.
Some eye doctors blame dry eye on problems with the meibomian gland, one of the sources of tear film. An article in Optometry Times discusses ways to clear blockages of the meibomian gland including the potentially painful squeezing of the gland (by a medical professional) or the less aggressive (though also potentially less effective) application of warm compresses to melt the obstruction.
