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Published on: March 19, 2017
Absolute thresholds in human infants exposed to continuous illumination
Insights
Continuous light exposure in neonatal intensive care units (NICUs) did not cause visual deficits in preterm infants. Research found no evidence of functional damage to infant vision from NICU light.
Area of Science:
- Ophthalmology
- Neonatal Medicine
- Developmental Neuroscience
Background:
- Continuous illumination in neonatal intensive care units (NICUs) is a potential risk factor for visual system damage in nonhuman species.
- The impact of prolonged NICU light exposure on visual development in human infants remains incompletely understood.
Purpose of the Study:
- To investigate whether long-term, continuous light exposure in the NICU leads to measurable visual deficits in preterm human infants.
- To assess potential functional damage to rod and cone vision in infants exposed to NICU illumination.
Main Methods:
- Utilized the forced-choice, preferential-looking technique to measure visual detection thresholds in preterm infants.
- Compared visual acuity and light detection thresholds between preterm infants with extended NICU light exposure and term-born controls with minimal exposure.
Main Results:
- No significant differences were observed in absolute thresholds for light detection between the light-exposed and control infant groups.
- Infants exposed to continuous NICU illumination performed comparably to controls on photopic visual acuity screening.
Conclusions:
- The study found no evidence of functional damage to either rod or cone vision in infants exposed to continuous illumination in the NICU.
- Current data suggest that typical NICU lighting conditions may not impair visual development in preterm infants, though further research is warranted.
Abstract:
Continuous illumination at low-to-moderate photopic levels can cause damage to the visual system in nonhuman species. Therefore, the authors sought to determine whether behaviorally measurable visual deficits occurred in young human infants who had been exposed to long-term, continuous illumination in a neonatal intensive care unit (NICU). Using the forced-choice, preferential-looking technique, the authors measured absolute thresholds for detection of a 502 nm stimulus in nine preterm infants who had been exposed to 13 to 46 days of continuous room illumination. Nine infants born at term, who had experienced less than or equal to 5 days of continuous illumination, served as controls. The thresholds for the light-exposed and control infants did not differ. In addition, the light-exposed infants did not differ from control infants in their performance on a rapid acuity screening under photopic conditions. Thus, the present data provide no evidence of functional damage to either rod or cone vision in infants who had been exposed to continuous illumination in an NICU. Some limitations to the generality of these conclusions are discussed.
