many thanks for your attention,
I visited an Ophthalmologist n he said it,s because of a kind of Eye swelling (i dont know how exact i,m in translating of this, my naitie lang. is persian) ,so he prescribed sterile eye drops as below :
1.Cromolyn - every 12 hours
2.Fluocort - as if it was necessary
It may be due to dryness. Trying using artificial tears.
Dr. O.