Dry eyes are caused by a lack of tears. Tears are necessary for the normal lubrication of your eyes and to wash away particles and foreign bodies.

If you have dry eyes, you will feel a burning, scratching, or stinging sensation. You may also have strained or tired eyes after reading, even for short periods of time. If you wear contacts, they will likely feel uncomfortable. Having dry eyes for a while can lead to tiny abrasions on the surface of your eyes.

Common causes of dry eyes include:

• Aging
• Dry environment or workplace (wind, air conditioning)
• Sun exposure
• Smoking or second-hand smoke exposure
• Cold or allergy medicines
• An eye injury or other problem with your eyes or eyelids (like a drooping eyelid or bulging eyes)
• Sjogren's syndrome -- includes dry eyes, mouth, and mucus membranes, and often rheumatoid arthritis or other joint disorder
• Previous eye surgery