How can you prevent dry eyes? i have been sleeping for many hours every night. what causes dry eyes?

Dry eyes: Follow up with opthalomologist. Dry eyes can be from lenses ,allergies,use of antihistamines or from autoimmune disease like rheumatoid arthritis, lupus, sicca syndrome(Sjogren's),isolated eye disease. In the short term uses drops like Systane, because if they stay dry you can have abrasions but you must seek medical attention see a doctor this week.