The Illuminant in the Prevention and Phototherapy of Hyperbilirubinemia

Light is known to promote many chemical events other than those resulting in vision - the primary concern of the illuminating engineer. The literature is replete with examples of photochemical phenomena ranging from degradation or fading of organic and inorganic dyes, pigments and other materials to synthesis of industrial chemicals and sustenance of life itself. Generally speaking, these are of peripheral interest to the illuminating engineer by definition.

The instant case involving the first light to which newborn babies are exposed is, however, an exception for it requires proper illumination of hospital nurseries from both the standpoint of the illuminating engineer and the medical phototherapist whose respective requirements may conflict. Superimposed upon the basic conflict - which does in fact exist - is a failure on the part of both to understand the others' jargon.

The purpose of the present paper is to review the elements leading to the conflict and misunderstanding and to put them in a perspective more amenable to scientific evaluation. At the same time, it provides both disciplines with essential illuminant data in accurate tabular form, allowing convenient interconversion between the various systems of units involving illuminance in footcandles (lux), irradiance in micro-watts per square centimeter, and quantum densities in quanta per second per square centimeter.