There are numerous external factors that can contribute to chronic dry eyes. Continuous exposure to sunny, dry or windy weather, heaters, air conditioners, fans, arid high altitudes including plane travel can increase the rate of evaporation of tears from the surface of your eyes. Working at a computer and staring at a screen for hours at a time can also exacerbate symptoms.
Dry eye syndrome can also be caused by biological issues. We produce fewer tears as we age, producing only 40% of the lubricating tears we produced as teenagers by age 65. Additionally, hormonal changes (especially in women can effect the tear film. Diabetes, hypertension, autoimmune disease and even allergy medications can lead to dry eye and ocular discomfort as well.