Dry eye results from either not having enough tears to keep the eye moist, or not producing the right quality of tears to protect the eye and prevent evaporation. In either case, the result is that dry, gritty feeling that just won’t go away.
Many factors can cause dry eye, including:
Age: As we age, our eyes produce fewer tears and the quality of those tears declines. Most of us older than 65 will experience dry eye at some point.
Gender: Women are more likely than men to experience dry eye. Hormonal changes due to menopause are a common cause, though the exact mechanism is not fully understood. Several studies have shown an increase in the severity of dry eye among women who use oral contraceptives.
Diet: A diet that is low in omega-3 essential fatty acids, or has a high ratio of omega-6 to omega-3 fatty acids has been linked to an increase in dry eye. Vitamin A deficiency is also associated with dry eye. A small 2015 study found that women with low vitamin D levels had dry eyes as measured by three different tests.
Medicines: Some medicines such as antidepressants, antihistamines, treatments for overactive bladder and even glaucoma eye drops can cause dry eye.
Health conditions: Dry eye is a symptom of some chronic conditions, such as the autoimmune disorder Sjogren’s syndrome, diabetes, rheumatoid arthritis and even acne rosacea. In addition, people with thyroid problems and hepatitis C are more likely to report dry eye symptoms.
Lifestyle: Years of wearing contact lenses, exposure to cigarette smoke and living in a dry or windy climate can all contribute to dry eye. So can staring at a screen for hours, working in a low-humidity environment and exposure to pollen and other common allergens.
Eye surgery: People who have had refractive eye surgery or cataract surgery usually need to use artificial tears to keep the eyes moist. Dry eye is common after blepharoplasty, the surgery to improve drooping eyelids. For those with preexisting conditions of dry eye, an eyelid lift can make it worse.