According to your description, it is possible that your eyes get conjunctivitis, which is the inflammatory reaction of the conjunctiva to the outside or the organism itself, or your eyes get tracoma, which presents itself as itchy eyes and sand-like particles on the surface of the palpebral conjunctiva. There are several reasons to cause conjunctivitis, therefore you had better go to the doctor's to have an eye examination to find out the exact cause, so that you can tke correspondent treatment. If your conjunctivitis is caused by bacteria, then you can use antibiotic eye drops such as tobramycin to apply into your eyes two or three times a day. If your conjunctivitis is caused by viruses, then you can use antiviral eye drops. As to tracoma, it is a kind of chronic communicable eye disease caused by chlamydia trachomatis, and it is likely that you get infected by other people who get tracoma. You should also go to the doctor's for medical treatment.