As a lubricant to relieve dryness of the eye. As a protectant against further irritation of the eye. For temporary relief of burning, irritation, and discomfort including exposure to wind or sun. Great for nighttime. Extra strength for daytime. Patented electrolyte balance. TheraTears Liquid Gel is just the right thickness to provide a less blurring, non-crusting, protective film that is ideal for nighttime use. It is also ideal for patients who need soothing longer-lasting protection during the day. The thicker protective film makes your eyes feel better longer and the increased corneal contact time provides more time for TheraTears to work. And unlike other gels, TheraTears is preservative free so there is no preservative-induced irritation. While you sleep all you feel is the soothing relief of TheraTears, and during the day you can use TheraTears as often as you like.