The goal of phototherapy is to use visible light energy to facilitate the breakdown of bilirubin in the blood. The devices that provide phototherapy do not use ultraviolet light, thus sunscreen is irrelevant. The use of direct sunlight should be discouraged because it does contain UV light and can be harmful. To maximize efficiency, as much of the infant skin should be exposed to visible light rays as possible. However, infants should receive eye protection. Even though the light is visible rather than ultraviolet this can still damage retinal tissue. Neonates may not be able to regulate body temperature efficiently, so the nurse must monitor the skins temperature to avoid overheating. Adequate nourishment and hydration is also important.