Bilirubin and Light

What is Bilirubin?

Bilirubin is a yellow compound, which occurs naturally when red blood cells die. The liver of premature infants frequently is not developed enough to remove this toxic substance, causing the disease jaundice . If the bilirubin level becomes very concentrated, then the babies can experience brain damage, and retardation, and even death may result. The most effective treatment for it usually consists of simple exposure to intense visible light. Ultraviolet light (UV) isn't needed and would be harmful. The visible light used is from a phototherapy unit, which is usually made up of four "Deluxe Cool White" flourescent lamps, which radiate from 300 ftc to 480 ftc. ( Ftc are a measure of radiation from a light source.) To read articles about OSRAM.(The company that supplies many of the "Deluxe Cool White lamps", search for bilirubin on the website to find out more information about the lamps)

Websites about recoveries of babies from jaundice, not all the "light"aspect information is correct:

Baby Joshua
Does Joshua need protection from UV radiation?
Baby Laura
Is that really a bank of Ultraviolet lights?

What is UV light?

Ultraviolet radiation is 400 nm to 100 nm long on the spectrum scale. Ultraviolet radiation could cause (from UV-B and UV-C zones) reddening of the skin and conjunctivitis (inflammation of the conjunctiva of the eye). UV-B is also what causes melanogenesis skin-tanning and contributes to skin cancer in certain individuals. The ultraviolet rays of wavelength shorter than 200 nm shouldn't worry you, because they are absorbed by air and even have a special name, "vacuum UV." Keep in mind that all boundaries between adjacent areas of the electromagnetic spectrum are fuzzy. You shouldn't assume that radiation at 199 nm is completely absorbed in air, while radiation at 201 nm is transmitted. All of these numbers are approximations.

How does UV light contribute to our health?

The most important and direct effect of UV light is it's role in the formation of vitamin D. We need vitamin D in order to collect calcium needed for maintaince and formation of our bones and teeth. Even though we get some of the calcium from food sources, almost 90% of it comes from a reaction of 7 dehydrotachysterol and UV radiation between 250 and 315 nm. Some illnesses, like rickets in children and softening of the bones in the elderly population could be prevented by small quantities of UV radiation.



Can sunlight be hazardous?

Yes, be careful,because direct sunshine can be hazardous to unprotected eyes. A report from Washington DC state that a group of babies near the nursery windows had sometimes been left lying with the sun in their faces, exposed to light intensities in excess of 400 ftc. Most of them went blind. The authors of the report computed the chances are 199 out of 200 that it was this exposure to sunlight, which had blinded the babies.

If you want to learn more, try:

Website by Sofya Maslyanskaya
Student, at the University of Stony Brook
March 13, 2001.