How it works
Your body reads the time of day from light. NOCTRA lenses filter blue and harsh white light in different amounts, and the five work as one system to help you protect, perform and recover from morning to night.
01 · Your circadian rhythm
Give your brain the right light signals.
Your body runs on an internal clock of roughly 24 hours. It helps time daily patterns of alertness, sleepiness, body temperature and hormones, and light is the main signal that keeps it on time.
380nm
460–490nm
580nm
780nm
The body clock’s light sensors (ipRGCs) are most responsive to blue light, around 460–490nm.
About 24 hours
Your body keeps time.
Cells throughout the body follow a roughly 24-hour rhythm, coordinated by a master clock in the brain.
Light is the main cue
Light sets the clock.
Light reaching your eyes each day helps keep that clock aligned with the world outside. Meal times and activity play a smaller role.
A dedicated sensor
Your eyes have a light meter.
Besides the rods and cones you see with, the eye has light-sensitive ganglion cells (ipRGCs) that report light levels to the body clock. They respond most to blue light.
02 · Modern light
Daylight, all evening long.
For most of history, evenings were lit by the sun going down and by firelight. Today, screens and LED lighting keep blue-rich light around long after sunset.
Screens
Close to your eyes, for hours.
Phones, tablets and laptops use LED backlights with a strong blue component, and we often look at them late into the evening.
Indoor lighting
Cooler, brighter rooms.
Energy-efficient LED and fluorescent lighting is often cooler and bluer than the warm bulbs it replaced.
Late nights
Mixed signals.
Research suggests bright light in the evening, especially blue light, can shift the timing of the body clock, telling it that it is still daytime.
03 · How colour helps
Colour changes the message.
A tinted lens works as a filter: it decides which wavelengths of light reach your eyes, and how much of each.
Wavelength filtering
Warmer tint, less blue.
Yellow, orange and red tints absorb more of the short, blue end of the spectrum. The deeper the tint, the more of the 380–500nm band is filtered. See the supplier-tested figures below.
Matched to the hour
Lighter by day, warmer at night.
Lighter tints filter less, so colours stay close to natural for daytime work. Deeper tints filter more, for evenings when you want warmer light around you.
How it feels
Warm light, calmer mood?
Many people find warm, amber light feels more relaxing than cool white light. That’s personal comfort rather than a health effect, and responses vary.
04 · Lens technology
Coating, tint, and what they block.
Not all blue-light lenses work the same way. Here’s what the terms mean, and how NOCTRA lenses are rated.
Coating vs tint
Surface or substance.
A blue-light coating reflects a small slice of blue light from the lens surface and keeps the lens almost clear. A tint absorbs light within the lens itself, so it can filter far more.
380–500nm
Rated by the blue band.
Each NOCTRA lens is rated by the share of 380–500nm light it blocks, from about 20% (Halo) to about 99.9% (Solace). Figures are supplier-tested, not yet independently verified.
UV400
UV protection.
UV400 means a lens blocks ultraviolet light up to 400nm. Every NOCTRA lens, from Halo to Solace, is UV400.
Safety
Dark lenses and driving.
Deep orange and red lenses change how you see colour, including traffic and brake lights, and cut the light reaching your eyes. Circadia: day driving and the drive home only. Solace: not for driving. Halo, Lumen and Shift: day and night driving.
05 · The spectrum
How much each lens filters.
Approximate share of 380–500nm light blocked by each lens. Figures from supplier in-house lens reports.
380nm
500nm
600nm
780nm
Blue band measured: 380–500nm
HALO
All day · Clear
~20%
LUMEN
Focus · Light yellow
~42%
SHIFT
Deep focus · Dark yellow
~82%
CIRCADIA
Evening · Orange · Day driving & the drive home
~98%
SOLACE
Night · Deep red · Not for driving
~99.9%
Supplier-tested, not independently verified. Shows blocking across the 380–500nm band only; full transmission curves to be published if independent lab data is obtained.
06 · A day with NOCTRA
Protect. Perform. Recover.
An example routine. Every lens protects; the system just moves from lighter lenses earlier to warmer lenses later. Shift the times to match your day.
Morning
Day
Evening & night
Daylight
No lens / Halo
HALO
Desk & phone
LUMEN
Focus blocks
SHIFT
Deep work
CIRCADIA
After work · Evening
SOLACE
Before sleep
Sleep
Lenses off
By day
Clear or lightly tinted lenses take the edge off harsh screens and office LEDs while keeping colours natural.
After work
Swap to a warmer lens to wind down while screens and lights stay on.
Before sleep
Our strongest filter for the last hour. Not for driving.
07 · Honest testing
What we know, and what we don’t claim.
Clear about the evidence, and about its limits.
Measured
Supplier lens reports
Blocking figures come from our lens supplier’s in-house test reports. They have not yet been verified by an independent lab.
Safety
Driving guidance
Circadia and Solace strongly change how you see colour, including traffic lights. Circadia is for day driving and the drive home only; don’t wear Solace to drive or operate machinery.
Sources
Educational information only.
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