Bili lights

Alternative names

Bili lights (phototherapy) are used to help infants with jaundice, a yellow coloring of the skin and eyes related to abnormal liver function.


Phototherapy is performed on infants who have elevated levels of bilirubin in the blood. Blue fluorescent lamps generate specific wavelengths of light that help break down bilirubin into nontoxic water-soluble components that can then be excreted.

Bilirubin in the blood is normally converted by the liver to an easily excretable form. A newborn infant’s liver can only convert a limited amount of bilirubin into this form. If blood levels of bilirubin become too high, the liver may be overwhelmed, leading to sustained high levels in the blood.

When this happens, bilirubin may enter body tissues, producing the characteristic yellow eyes and skin of jaundice (hyperbilirubinemia). Bilirubin also may enter brain tissue, where it can cause permanent brain damage if levels become too high.

The treatment for newborn jaundice depends on three factors: the birth weight, the concentration of bilirubin in the blood, and the newborn’s age in hours. In severe cases of elevated bilirubin in a low-birth-weight newborn less than 24 hours old, an exchange transfusion may be preferred over phototherapy. With very high bilirubin concentrations, regardless of age and weight, an exchange transfusion may be the best option.

Phototherapy involves the exposure of bare skin to fluorescent light. Specific wavelengths of the light break down the bilirubin. The newborn (without clothes or in a small diaper) is placed under the fluorescent lights. The eyes are covered to protect them from the bright light. Body temperature, vital signs, duration of treatment, positioning of the bulbs, and the newborn’s responses are carefully noted. The child is turned frequently to maximize the effects of therapy. Some children receive phototherapy at home - a nurse visits daily, obtaining a sample of blood for testing.

Because dehydration may result from exposure to the lights, intravenous fluids may be required. Bilirubin levels are monitored and when the levels have declined sufficiently, the infant can be taken from the phototherapy area.

Johns Hopkins patient information

Last revised: December 8, 2012
by Armen E. Martirosyan, M.D.

Medical Encyclopedia

  A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | 0-9

All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.