Circadian-Informed Lighting

"Circadian Lighting" may sound like an over-used buzzword these days - but peel back the polish and you'll uncover something real: A new dimension in lighting design, grounded not in fleeting trends, but physiology.

Let's take a quick look at the following:

1. What is circadian lighting, really?
2. Think of it like a dose
3. Is circadian lighting relevant in Australia & New Zealand?
4. Why simply meeting the standards isn’t enough
5. What we are doing at Eagle Lighting

1. What is circadian lighting, really?

Circadian lighting uses electric light to support the body’s internal clock, especially your sleep/wake rhythm and broader hormonal cycles. These effects are driven by a third type of light-sensitive cell in the eye called intrinsically photosensitive retinal ganglion cells, or ipRGCs for short.

Unlike rods and cones, which help us see, ipRGCs don’t directly(*) contribute to visual images. Instead, they detect overall light levels in the environment and send timing signals to parts of the brain that regulate sleep, mood, alertness, and hormones, including the suprachiasmatic nucleus (SCN), often called the body’s master clock.

This is why it's important to separate what we "see" from what our body "senses".

(*) While ipRGCs don’t form images in the traditional sense, they do contribute to how we perceive brightness. They interact with rods and cones through complex retinal circuits, so no photoreceptor works in isolation. ipRGCs receive input from rods and cones - and send signals back, blurring the line between visual and non-visual effects. They’re also not a single cell type, but a family of subtypes, each specialized for different tasks. Understanding their exact role is still an active area of research.

2. Think of it like a dose

Circadian lighting isn’t about simply increasing the amount of light - it’s about delivering the right kind of light at the right time. A helpful way to think about it is like medication: it's not about taking more, but about taking the correct dose.

Here’s how the analogy works:

• Illuminance × Duration → How many tablets you take per day

• Spectral Content → How many milligrams of the active ingredient are in each tablet

• Timing → Whether you take the tablet in the morning or at night

If you take the wrong dose or take it at the wrong time, you may get the opposite effect of what you intended.

3. Is circadian lighting relevant in Australia and New Zealand?

When people hear about circadian lighting, they often assume it’s mainly useful in places like northern Europe, where long, dark winters disrupt natural light cycles. It’s an understandable assumption. After all, if you live somewhere sunny, how much difference can lighting really make?

Quite a lot, it turns out.

Circadian-informed lighting isn’t just for far-northern climates or scientific journals. It’s highly relevant to how we live and function indoors—where we now spend the overwhelming majority of our time.

Like most developed nations, Australians and New Zealanders spend 80–100% of their time indoors, often in spaces where artificial light dominates (Source: Victorian Department of Health). And that light often fails to support our biological rhythms.

Over the past few decades, neuroscience has shown just how profoundly light influences our sleep, mood, alertness, and well-being. Yet this understanding is still rarely reflected in mainstream lighting design.

The result? Many of our homes, offices, schools, and hospitals are still lit in ways that work against how our brains and bodies are wired to respond to light.

4. Why simply meeting the standards isn’t enough

Walk into almost any office, home, hospital or aged-care facility that meets current lighting standards—like AS/NZS 1680—and you might assume the lighting is doing its job. On paper, it is. But in reality, it’s falling short—especially when it comes to supporting our health.

Modern neuroscience has shown us that light influences far more than just vision. It also affects our internal biological clock—our circadian system—through non-visual pathways that respond to specific qualities of light, particularly blue-enriched wavelengths measured as Melanopic Equivalent Daylight Illuminance (Melanopic EDI).

Most regularly occupied spaces today provide lighting levels far below what’s needed to support healthy circadian rhythms. Offices typically deliver horizontal illuminance between 200 and 500 lux. In homes, it’s often closer to 100 lux. In aged-care facilities—where circadian health is especially critical—light levels are usually even lower, more inconsistent, and less supportive of residents' biological needs.

In short, compliance with the standard doesn’t mean the lighting is optimal for human health. To design truly human-centric spaces, we need to go beyond the minimum and start aligning lighting with how people actually function—visually, biologically, and behaviourally.

5. What We’re Doing at Eagle Lighting

At Eagle Lighting, we believe light should do more than meet technical benchmarks - it should contribute to human wellbeing. That’s why circadian lighting isn’t just a catchphrase to us; it’s a guiding design principle backed by science.

Our Approach to Circadian-Informed Lighting

We measure our own spectral data

All our luminaires are tested in-house using our NATA-accredited photometric laboratory. We gather full spectral power distributions - no assumptions or default templates, because precise input is essential when designing for human biological effects.

We apply validated circadian metrics

We use internationally recognised methods and standards, including:

• CIE S 026/E:2018 and its Toolbox for M-DER and M-EDI calculations

• ANSI/IES RP-46-23 and IES TM-18-08 for integrative and circadian lighting principles

• CIE Position Statement PS001:2024, which defines proper light at the proper time

We also track evolving frameworks like the Circadian Stimulus (CS) model from the LHRC and UL DG 24480, recognising that this is an active area of scientific development.

We design for vertical eye-level illuminance

Circadian-effective light is delivered primarily via the vertical plane. That’s why we optimise our designs for vertical illuminance at eye level - not just horizontal lux on a desktop.

Local, Evidence-Based Lighting

All our work is built on peer-reviewed science and calibrated for real-world Australian and New Zealand conditions. Because human-centric lighting shouldn't be a premium feature - it should be the baseline.