Is junk light
making us
ill?
Most of us spend our lives under artificial light. Peer-reviewed research is now showing what that does to our eyes, our sleep, and our health.
See the Evidence
Think of it like junk food.
Like junk food, junk light is everywhere. It’s cheap. And most people don’t realise it’s affecting them. The spectrum is incomplete. Heavy on blue, deficient in red.
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What junk light does to your vision.
Shorter-wavelength light creates more scatter inside the eye, and the effect is measurably worse in lighter-pigmented eyes. You experience it as more glare, weaker contrast, and text that feels harder to hold steady.
It gets worse with age
As the lens yellows with age, it scatters more light, and the contrast you rely on fades.
Reading suffers first
Short-wavelength light can cause the lens itself to scatter light internally, creating a haze strong enough to affect how clearly you see, even at exposure levels classified as safe. Higher colour temperature lighting is also linked to measurable fatigue during prolonged reading.
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Your body clock runs on light.
We built our lights to help you see more clearly. But there is growing evidence that the spectrum of your light matters for reasons you cannot see at all, and may well feel.
A hidden sensor in the eye
Room light is enough
Deep sleep is affected too
Just two hours of blue-enriched evening light reduced slow-wave brain activity in the first sleep cycle: the deep, restorative phase your body depends on to recover.
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It doesn’t stop at sleep.
When your body clock is chronically disrupted, the effects reach further than you might expect.
- Obesity Disrupted sleep changes how your body stores fat and handles food
- Type 2 Diabetes Poor circadian health is linked to how your body manages blood sugar
- Heart Disease The American Heart Association now identifies circadian disruption as a contributor to heart disease
- Certain Cancers A review of 75 studies found more than double the risk of breast cancer among night workers, with prostate and colorectal cancer also elevated
In 2019, IARC classified night shift work as “probably carcinogenic to humans”. The reason? Chronic disruption to the body’s circadian rhythm.
International Agency for Research on Cancer, 2019Sources
Change the light. Change the day.
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What does the difference look like?
This is a representation, but the principle is real. On the left, a narrow-spectrum LED forces your eyes to fill in what the light leaves out. On the right, a fuller spectrum does the work for you. Drag the slider. In person, the difference is even more striking.
Built on the evidence.
Forty years ago, we set out to build a reading light that worked with your eyes instead of against them. The research on this page explains why that approach works, and what else it may do for you.
Our Daylight Wavelength Technology™ delivers a continuous, full-spectrum output instead of the narrow spikes common in standard LEDs. Sharper text, truer colours, and markedly less strain. You notice the difference the moment you switch it on.
HD Pro
Full control. Full spectrum.
Our flagship. Dimmable, with a shapeable beam you can direct exactly where you need it. 98% colour accuracy. Available as Table or Floor.
From £449.99
90-day risk-free trial
Try the HD Pro Risk-Free
HD Essential
Same spectrum. Simpler design. Best value.
The same Daylight Wavelength Technology™ in a streamlined design. 98% colour accuracy. Table and Floor versions.
From £349.99
30-day risk-free trial
Try the HD Essential Risk-Free“The impact was immediate. Something rarely experienced with other purchases.”Mr Griffin, Leicestershire • Verified Buyer
Questions worth asking.
About the researchNo. Every claim on this page comes from independent, peer-reviewed research published in scientific journals. Serious Readers is reporting what scientists and clinicians have found, not making health claims about our products. We link to every source so you can verify them yourself.
All sources are indexed on PubMed or published in peer-reviewed journals. They include studies from the Journal of Neuroscience, Circulation (American Heart Association), and Experimental Eye Research. Full references are listed at the bottom of this page.
Light quality is one piece of a bigger picture. A better reading light won’t change your prescription or cure a medical condition. But the research consistently shows that the spectrum of light you’re exposed to affects visual comfort, sleep quality, and alertness. Improving it is a simple, measurable change you can make today.
‘Daylight’ usually means a cooler colour temperature, not a more complete spectrum. A bulb can look whiter and still have the same blue spike and red gaps. Our Daylight Wavelength Technology™ is measured to TM-30 standards: Rf 98 colour fidelity, with a continuous spectrum from 380–780nm. See the lab report →
Ready to see the difference?
Every light in the range includes a risk-free home trial. HD Pro: 90 days. HD Essential: 30 days.
Choose Your LightFree UK delivery. Free returns. No questions.
Sources
All sources are peer-reviewed. Indexed on PubMed unless otherwise noted.
Vision & Eyestrain
Coppens JE et al. “Wavelength dependence of intraocular straylight.” Experimental Eye Research, 2006. PMID: 16293245
Zuclich JA et al. “Near-UV/blue light-induced fluorescence in the human lens.” J Biomed Opt, 2005. PMID: 16178654
Kohnen T, Hammond BR. “Blue light filtration: effects on visual function and systemic health.” Clinical Ophthalmology, 2024. PMID: 38835885
Fu X et al. “Correlated color temperature and visual comfort.” Sustainability, 2023. DOI: 10.3390/su15043826
Sleep & Circadian Rhythm
Brainard GC et al. “Action spectrum for melatonin regulation.” J Neuroscience, 2001. PMID: 11487664
Gooley JJ et al. “Room light before bedtime suppresses melatonin.” J Clin Endocrinol Metab, 2011. PMID: 21193540
West KE et al. “Blue light from LEDs: dose-dependent melatonin suppression.” J Appl Physiol (1985), 2011. PMID: 21164152
Chellappa SL et al. “Evening blue-enriched light impacts sleep.” J Sleep Research, 2013. PMID: 23509952
LeGates TA et al. “Light as a central modulator of circadian rhythms, sleep and affect.” Nature Reviews Neuroscience, 2014. PMID: 24917305
Dijk DJ. “Regulation and functional correlates of slow wave sleep.” J Clinical Sleep Medicine, 2009. PMID: 19998869
Alertness & Cognitive Function
Vandewalle G et al. “Wavelength-dependent modulation of brain responses.” Cerebral Cortex, 2007. PMID: 17404390
Viola AU et al. “Blue-enriched light improves alertness, performance and sleep.” Scand J Work Environ Health, 2008. PMID: 18815716
Vandewalle G et al. “Light as a modulator of cognitive brain function.” Trends Cogn Sci, 2009. PMID: 19748817
Mu Y et al. “Alerting effects of light: systematic review and meta-analysis.” Sleep Med Rev, 2022. PMID: 35142669
Long-Term Health Risks
Systematic review: “Circadian disruption and cancer risk.” 75 studies, 2003–2023. PMC: PMC12529610
Baidoo A et al. “Circadian disruption and cardiometabolic disease risk.” Obesity, 2023. PMID: 36750239
American Heart Association. “Circadian health and cardiometabolic disease.” Circulation, 2025. PMID: 41147137
International Agency for Research on Cancer (IARC). “IARC Monographs evaluation of the carcinogenicity of night shift work.” 2019. IARC
IARC Working Group. Night Shift Work. IARC Monographs on the Identification of Carcinogenic Hazards to Humans, Vol. 124, 2020. NCBI Bookshelf
Sletten TL et al. “Health consequences of circadian disruption.” Sleep, 2020. PMID: 31930347
Indoor Exposure
Klepeis NE et al. “The National Human Activity Pattern Survey.” J Expo Anal Environ Epidemiol, 2001. PMID: 11477521
Light Source Characteristics
Holzman DC. “What’s in a color? The unique human health effects of blue light.” Environmental Health Perspectives, 2010. PMC: PMC2831986
Shen S et al. “Red-emitting phosphors for white LEDs.” RSC Advances, 2021. DOI: 10.1039/D1RA01291F