Blue light, sleep,
and the lenses
that matter

Yes. Melanopsin sensitivity peaks at around 480nm but extends into the green spectrum up to approximately 600nm. Amber lenses that filter most blue light but leave the green range largely open are still allowing melatonin-suppressing wavelengths through. Full circadian protection requires addressing both blue and green wavelengths, not blue alone. This is the gap most evening glasses leave open. Read the full article on green light and sleep.

Melatonin is the hormone your body uses to signal darkness. It does not cause sleep directly. It tells every system in your body that night has arrived and the biological transition toward rest should begin. When melatonin is delayed or suppressed, the cascade of hormones that regulate recovery, immune function, mood, and energy all shift with it. Sleep is the entry point. The downstream effects extend well beyond how quickly you fall asleep.

More than most people expect. A phone held 25-30cm from your face delivers a concentrated dose of blue and green wavelength light to your retinas. Duration compounds the effect: an hour of screen use during the two hours before bed, when melatonin onset is beginning, is not a minor insult. Research confirms melatonin suppression can persist for one to two hours after exposure ends.

Partially. Night Shift shifts the colour balance of your screen toward warmer tones, which reduces blue output. It does not fully block the wavelengths that activate melanopsin. Studies examining software night modes have found they reduce, but do not eliminate, melatonin suppression. For meaningful circadian protection, a spectrally verified lens covers more of the relevant range than software filtering can.

Research suggests melatonin suppression can persist for one to two hours after blue light exposure ends. To meaningfully protect melatonin onset, reducing blue and green light exposure at least 90 minutes to two hours before your intended sleep time is recommended. Stopping screens in the final 30 minutes will have less impact than starting the low-light window earlier.

Three lenses, one circadian system. The Daytime lens (yellow) filters 83% of blue light for screen use during the day without affecting melatonin. The Night lens (amber) filters up to 95% of blue light for use from sundown onward. The Night+ lens (red) blocks 99.9% of blue light and 97% of melatonin-suppressing green wavelengths up to 600nm for the 1-2 hours before sleep. All three are independently spectrometer verified.

Night+ is the lens designed specifically for sleep. It addresses the full melatonin-suppressing spectrum: 99.9% of blue light and 97% of green wavelengths up to 600nm, the complete range where melanopsin remains active. If you use screens in the hour or two before bed, have difficulty falling asleep, or have tried amber glasses without the results you expected, Night+ provides the most complete biological protection available in a wearable lens.

Both reduce melatonin suppression. The difference is in the green spectrum. Amber lenses (Night) filter up to 95% of blue light but allow a portion of the green range through. Red lenses (Night+) block 99.9% of blue and 97% of green to 600nm. For people who use screens late or want the most complete circadian protection, Night+ closes the gap that amber leaves open.

Both lenses have a place in a circadian routine, and many people use both. Night (amber) is designed from sundown onward: it filters up to 95% of blue light while maintaining around 50% overall light transmittance, so you can move around the house and go about your evening without straining to see. Night+ goes further: it filters the full blue and green spectrum together and reduces overall light transmittance to under 20%, making bright lights appear noticeably dim. Many people wear Night from sundown, then switch to Night+ in the final hour or two before bed.

The Daytime lens filters 83% of blue light at screen-relevant wavelengths during the day. Blue light during daylight hours does not suppress melatonin: your body does not produce it until evening. Daytime filtering reduces visual fatigue and eye strain during long hours at a screen without affecting alertness or your circadian rhythm. It is the daytime half of a complete circadian protocol.

No. Each lens is designed for a specific phase of the biological day. The Daytime lens is for screen use during daylight hours. Night is for use from sundown onward. Night+ is for the 1-2 hour window before sleep. Using an evening lens during the day would reduce your experience of the daylight that supports a healthy cortisol rhythm and circadian anchor.

Yes. The Complete Circadian Set pairs the Daytime lens with Night+ in your choice of frame, covering both ends of the circadian day. It is the recommended starting point for anyone who wants full-spectrum circadian support from morning screen use through to sleep.

It means the lens has been tested by an independent laboratory using equipment that measures actual light transmittance across the visible wavelength spectrum. The blocking percentages Balterra publishes are not marketing estimates. They are third-party measured data. When we state Night+ blocks 99.9% of blue light, that figure comes from spectrometer testing, not from product copy.

Most blue light glasses are designed for daytime eye comfort, filtering 20-40% of blue light below 450nm. They are not designed for sleep. Balterra Night+ addresses the full melatonin-suppressing spectrum to 600nm, verified by independent spectrometer data. The spectral coverage, the verification process, and the precision of the claims are what separate a genuine circadian lens from a comfort lens.

Clear lenses typically filter 10-30% of blue light at the highest-energy wavelengths. The ipRGC pathway requires a meaningful reduction across the 460-600nm range to measurably affect melatonin. Clear lenses reduce glare and may ease visual fatigue, but they do not produce the spectral shift your circadian biology responds to. If clear glasses did not improve your sleep, the tint, not the concept, is the reason.

The primary suppression range runs from approximately 460nm to 600nm. Melanopsin sensitivity peaks around 480nm in the blue range and remains biologically active through the green spectrum to approximately 600nm. Blue light is the dominant suppressor. Green light continues the signal at lower potency. A complete evening lens addresses both ranges, which is why Night+ is designed to filter to 600nm.

1-2 hours before your intended sleep time. This is the window when melatonin onset is beginning naturally, and when unfiltered blue and green light has the most significant impact on delaying that process. Put them on after dinner or when evening screen use begins, and wear them until you turn out the lights.

Night+ is a deep red lens. Blues and greens are absorbed almost entirely and appear black or grey on screen. Reds and oranges remain vivid. Content stays fully readable, but you are seeing it through a narrow spectral window above 600nm. That absence is the point: the wavelengths your melatonin system responds to are simply not reaching your eyes. Most people adapt within one to two evenings.

Yes. Night+ works across any screen-present environment in the hours before sleep: phones, laptops, tablets, and televisions. The lens works regardless of the content or device. Blues and greens will appear dark, reds and oranges will remain vivid.

Most people notice the wind-down effect within the first two hours of putting them on: a settling of alertness and a quieter quality to the evening that signals sleep is coming. Deeper improvements in how quickly you fall asleep and how rested you feel on waking tend to compound over the first few weeks as your circadian rhythm stabilises. Consistency in timing matters: wearing them at the same point each evening gives your body a reliable signal to respond to.

Balterra glasses are currently non-prescription. They are designed to be worn over contact lenses or on their own. If you wear prescription glasses and want advice on the best approach for your situation, contact us at info@balterra.au.

Balterra offers a 30-day right fit guarantee. If the lens or frame is not right for you, you can exchange within 30 days of delivery. Full details are at balterra.au/policies/refund-policy.

Yes. If your country is not available at checkout, contact us at info@balterra.au with your shipping location, preferred frame, style, and lens and we will create a custom order for you.

Balterra was founded in Melbourne in 2025 by Kurtis and Racquel around a specific conviction: that the gap between modern life and ancient biology is one of the most consequential health problems people are not talking about. The circadian system evolved over millions of years. The light environment humans now live in is incompatible with it, and the effects accumulate quietly in sleep, hormones, energy, mood, and focus. When Kurtis and Racquel looked for eyewear that could genuinely help, they found a category more interested in marketing claims than in working with the biology. Balterra is what they built instead: every claim independently verified, every lens designed to do exactly what the science says it should.