artificial tears without preservatives are more expensive than bottled artificial tears with preservatives. Some patients confuse over the counter drops that contain tetrahydrozoline (i.e. Visine®), a vasoconstrictor, with artificial tears. Desensitization can occur with extended usage of drops containing tetrahydrozoline. Indications and effects The most common indication for artificial tear use is dry eyes. Risk factors for developing dry eyes includes increasing age, female gender, environments with low moisture, nutritional deficiencies, certain medications, and autoimmune conditions. Examples autoimmune conditions are Sjogren's syndrome, autoimmune thyroid disease, and uveitis. Patients with dry eyes may have an inability to produce adequate amount or quality of tears leading to a disruption in their tear film. In addition, those who wear contact lenses or have undergone eye surgeries such as LASIK are at increased risk of having dry eyes. Normal tears are important to keep the surface of eyes clean and moist and protect eyes from infections. They are composed of many components including enzymes that act as natural antibiotics, proteins that prevent bacterial growth, and nutrients. Without adequate lubrication, patients are at risk for infection as well as irreversible scarring and damage. Artificial tears are the recognized treatment of choice for this problem. Artificial tears work by adding similar lubricating elements that natural tears contain. This helps thicken and stabilize the pre-corneal tear film, prolonging tear film breakup time, and allowing for tears to properly protect the surface of the eyes. Most artificial tears do not require a prescription and can be used as often as needed. Patients who use artificial tears more frequently than four to six times a day should choose a brand without preservatives or one with non-irritating preservatives. Thicker artificial tears that come in the form of gel or ointments may be used in more severe cases as they last longer, although they may temporarily blur vision. In more severe cases, providers may prescribe a form of artificial tears that works to reduce inflammation in the tear glands in an effort to improve natural tear production and the quality of tears produced. Side effects and precautions Artificial tears have no reported interactions. The most common side effect of artificial tears is temporary blurry vision. Allergic reactions have been reported and are associated with itchy or swollen eyes, dizziness, and breathing problems. These symptoms warrant discontinuation of the drops and to see a physician immediately. Prescription drops may have additional side