Safety of neonatal phototherapy lamp exposure.

A routine review of light exposure within a neonatal intensive care unit is described following the introduction of a new model of neonatal phototherapy lamp. Spectral measurements were undertaken using a Bentham Dmc150 spectroradiometer system. Safety assessments were undertaken based on likely exposure of parents at the cot side, neonates in adjacent cots and the effectiveness of eye protection for neonates with direct phototherapy. An aphakic eye response was used for assessment of neonatal risk and the blue-light response for estimation of adult exposure using current ICNIRP guidelines. Such estimations indicated exposure levels of parents at the cot side and neonates in adjacent cots were within current established safe limits. The level of light blocking provided by the available neonatal eye protection was estimated to be entirely adequate and presented no hazard to the infant when correctly positioned over the neonate. It is likely, however, that an increased safety factor is potentially present for the neonate due to the fact that the neonate's eyes will typically be shut for over 50% of the time. It is identified, however, that the aphakic response is essentially associated with mature adult retinal cells, and that the maturing cells of the neonate may exhibit additional light sensitivity, especially in the case of premature infants. Changes in neonatal physiology associated with neonatal phototherapy are discussed, which may influence mechanisms of light-induced retinal damage.