Corneal cells on the surface of the eye are actively metabolized and repaired while the eye is sleeping to repair damage. Rohto Yohjunsui Alpha is an eye drop that focuses on this eye activity during sleep. Nutritional ingredients help the corneal cells' ability to repair themselves and promote the recovery of tired eyes by stimulating metabolism. It contains taurine, which nourishes the eye, promotes metabolism, and encourages recovery of tired eyes, and sodium chondroitin sulfate, which protects the stressed cornea by retaining moisture on its surface and preventing eye diseases. As an additive, we also added sodium hyaluronate, a viscous ingredient known as a water-retaining ingredient in beauty salves that has excellent moisture retention properties (viscosity agent in formulations). Whenever you feel your eyes are tired, such as when you use your eyes too much on a computer or smartphone, take off your contact lenses, or spend time in a dry room, apply a drop before going to bed. (We recommend applying the drops at least 5 minutes before bedtime.)