I have the same issue, due to Grave’s disease - was treated with irradiation of the thyroid. Since then suffered dry eyes with itching and burning and severe tearing of my eyes, to the point that it looked like I was crying. Doctor told me to start using Sustain eye drops. I’ve had good results since starting, but need to use them 4 to 5 times daily. At least they are over the counter, so not to expensive.