The Summary
This narrative review examined how light impacts non-visual brain functions, including cognition, mood, and biological rhythms, across a human lifespan. While specialized retinal cells drive these effects by detecting blue light, most research has focused exclusively on young adults. The authors synthesized evidence on age-related ocular shifts alongside pupil, melatonin, and cognitive responses from fetal development through older age. They found that evidence across childhood, adolescence, and older adulthood remains fragmented and underquantified, underscoring the urgent need for age-tailored research to inform future therapeutic light interventions.
Why this is interesting
Most lighting recommendations assume every brain responds identically, relying almost entirely on data from healthy young adults. However, as our eyes and neural pathways mature and age, our sensitivity to light changes dramatically. What boosts alertness or regulates biology in a twenty-year-old might not work for a child or a senior. Recognizing that light sensitivity evolves throughout life creates opportunities to design age-customized lighting in schools, homes, and eldercare facilities to better support mental performance and well-being.