This month, we welcomed you back to our Meaning of Light series and met with Kevan Shaw, co-author of Lighting Design for Health, Wellbeing and Quality of Light: A Holistic Approach to Integrative Lighting Whitepaper. Throughout his talk, Shaw challenged the traditional lighting paradigm. Most lighting has been designed with one primary purpose: to enable vision. But research increasingly shows that this visual-centric approach misses crucial non-visual impacts that light has on our health and well-being.
Integrative lighting considers not just how we see, but how we feel, think, sleep, and function. It’s a holistic approach that balances visual, biological, and emotional responses to light.
At the heart of this conversation lies a remarkable discovery: intrinsically photosensitive retinal ganglion cells (ipRGCs) in the eye. These cells regulate our circadian rhythms, our internal biological clocks. They are most responsive to blue light and influence our sleep-wake cycles, hormone production, and mood.
The right light, at the right time, can:
To design for biological health, we must go beyond lux and lumens. Melanopic Equivalent Daylight Illuminance (MEDI) is a metric that measures how light affects circadian systems, not just visual perception.
The consensus? For effective circadian support:
Timing matters. Bright, blue-rich light in the morning? Beneficial. That same light before bed? Disruptive.
As we’ve explored previously in the Meaning of Light, emerging research is exploring infrared (IR) and near-infrared (NIR) light’s potential role in supporting mitochondrial function. Incandescent sources naturally emitted IR, but LEDs and modern glazing cut it out almost entirely.
While still in early stages, this area could open new frontiers in health-supportive lighting.
LED lighting also brings unintended risks. Flicker can cause eye strain, headaches, and discomfort, especially for neurodivergent individuals. Metrics like PSTLM and SVM help quantify flicker, but even compliant systems can be problematic for sensitive users.
Photo-biological safety is another concern, especially with high blue peaks or failing phosphors in LED chips. While rare in quality lighting products, cheap imports and poorly regulated fixtures remain a risk.
Shaw outlined a revised design process that places users and timing at the core:
It’s not about creating medical-grade lighting. It’s about minimising harm and maximising well-being.
Shaw shared with us a case study, a care home facility based in Iceland, where rooms were outfitted with tunable LEDs, ambient amber lights, and motion-activated night cues. The lighting mimicked natural rhythms, cool and bright in the morning, warm and dim by evening. This exciting project is still being completed but we can’t wait to hear all about the beneficial effects it will have on residents once it is finished.
Though integrative lighting is not yet fully reflected in most codes, change is underway:
Energy codes, capital costs, and value engineering still challenge implementation. But for clients focused on health, productivity, and longevity, the long-term value of integrative lighting is becoming harder to ignore.
Designers must become educators, explaining these benefits to clients, project managers, and regulators.
Lighting is more than illumination. It’s a biological cue, a mood setter, and a health tool. As science deepens, so too must our design thinking. The goal isn’t to mimic the sun, but to align electric light with natural human rhythms, to create spaces that nurture us, body and mind.
Let’s go beyond vision. Let’s design for life.
If you missed this rather thought-provoking discussion or any of our previous sessions, head over to our YouTube channel.
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