Dry eye is a common ocular surface disorder. It refers to the instability of the tear film caused by abnormalities in the quality and quantity of tears from any cause, and is accompanied by symptoms of ocular discomfort, which can cause ocular surface tissue lesions (cornea and conjunctiva). Symptoms of dry eye include: *Redness of the eyes. *Irritation, foreign body sensation, burning and itching sensation in the eye. * Photophobia. *Blurred vision (relieved by blinking), fluctuating vision, and easy visual fatigue. *Can’t tolerate contact lenses. *Can’t tolerate environment with smoke and dust. What can cause dry eye? Abnormalities in any layer of the tear film structure can lead to dry eye. The most common cause of dry eye is a deficiency in the aqueous layer of the tear film. Who is at risk for dry eye? * Age: The tear glands’ ability to produce tears decreases with age, and after the age of 40, many people begin to feel symptoms of dry eye. *Gender: Women are more likely to suffer from dry eye than men due to changes in hormone levels that accompany menstruation, pregnancy and childbirth, and menopause. *Contact lens wearers: Soft contact lens wearers can cause accelerated tear evaporation. *Computer users: When using computers, blinking frequency is reduced, which will make tear evaporation increase. *Dehydration: Inadequate fluid intake can cause systemic dehydration or dry eye. *Alcohol and caffeine intake: both of these can cause dehydration or dry eye. *Environmental factors: Exposure to smoke, wind, air pollution, air conditioning and dry climates can cause eye irritation and dryness. Part of the airplane cabin with repeated circulation is particularly dry and can easily produce eye irritation. *Medications: Many medications, including antihistamines, medications to relieve symptoms of congestion, oral contraceptives, blood pressure control medications, medications for ulcers, and antidepressants can cause dry eyes. * Systemic diseases: These include diseases that can affect the body’s ability to produce tears, such as arthritis, diabetes, thyroid disease, asthma, and lupus. *Incomplete shut-eye sleep: Some people sleep with their eyes incompletely closed, which can lead to chronic dry eye. Is dry eye common? Dry eye is a very common ocular surface disease, especially in people over the age of 40. The prevalence of dry eye has been reported inconsistently, but in one study in the United States, it was shown that about 20% of people have dry eye. Some researchers believe that 75 percent of people older than 65 years of age have dry eye. What can you do to reduce your risk of dry eye? * Consume adequate amounts of water: at least eight glasses of water a day. *Avoid alcohol and coffee as much as possible. *Try to avoid prolonged use of computers. *Use an air humidifier in winter or dry weather. *Clean your contact lenses daily and replace them promptly. *Wear sunglasses with a good seal for outdoor activities (especially in windy weather). *Eat salmon or salmon weekly, and consider taking a daily Omega-3 fatty acid supplement.