The light around you decides how you sleep, focus and feel.
Your eyes don't just see: they tell your body what time it is. Each lens tint — yellow, orange and red — filters a different slice of the spectrum to give your body the right signal at the right hour.
Artificial light never switches off.
For almost all of human history, the only bright light came from the sun. After dusk, fire and candles gave off a warm, dim glow: the signal that the day was ending.
Today your nights are full of screens and LED light, just as bright and just as blue as noon. Your body can't tell a phone at 11 PM apart from the midday sun: it simply reads the light it gets and reacts.
That confusion delays the hormone that gets you ready for sleep and keeps you alert when you should be winding down. The result is feeling wired and exhausted at the same time.
A narrow slice of the spectrum runs your internal clock.
Visible light runs from 380 to 780 nanometers. Your body handles almost all of that range just fine. But one band, roughly between 415 and 530 nanometers — from blue-violet to blue-green — reads to your eyes as "it's daytime," no matter what the clock says. Sensitivity peaks near 480nm.
The highlighted zone is what most stimulates the cells in your retina that tell your brain what time of day it is. The more of that band you filter, the closer the light reaching your eyes gets to a warm evening instead of high noon. Each of our three lenses covers a progressively larger slice of it.
Each color filters a different slice of the spectrum.
Yellow, orange and red aren't just a look: each tint is chosen for how much blue light the hour actually calls for. The figures below come from lab spectral transmission measurements on each lens.
The gentlest filter
Cuts the most energetic part of the band — blue-violet — without darkening your view. Made for screen hours in broad daylight, when your body still needs bright light to stay alert, minus the overload that causes eye strain.
The middle filter
Widens the cut to cover nearly all blue, including the peak sensitivity zone of your internal clock. Built for the transition hours, when the sun starts dropping and your body should begin reading that the day is winding down.
The deepest filter
Blocks nearly all blue plus part of the green, letting mostly warm tones through. It's the optical equivalent of candlelight: for the hours before bed, when your body needs the clearest possible night signal.
From light to your biology, in three steps.
Every photon that reaches your eye follows the same path: retina, brain, hormone. The lens tint steps in right before the first one.
Your retina reads the time of day.
A special set of cells in your retina plays no part in vision: their job is to measure ambient light and tell your brain whether it's day or night.
The wrong signal arrives at night.
A lit screen after sundown sends a signal much like the midday sun. Your brain doesn't care where it came from: it only responds to the wavelength it receives.
The tint filters before the light reaches your eye.
Yellow, orange or red depending on the hour, each lens absorbs the band that confuses your internal clock and lets the rest of the spectrum through, so you keep seeing the world clearly.
Two hormones and a pair of eyes that never rest.
The light your eyes take in shapes when your body produces the hormones that set the rhythm of your day — and how hard your vision has to work through hours of screen time.
Cortisol
Your alertness hormone. It follows a daily cycle that starts high in the morning and tapers toward night. Bright light at the wrong hour can interfere with that natural decline.
Digital eye strain
Hours in front of a screen cut your blink rate and demand sustained close-up focus. That's where the dry eyes, the heaviness and the tired vision at the end of the day come from.
Melatonin
Your sleep hormone. Bright blue light in the hours before bed can delay its release. Filtering that band at night helps the sleep signal arrive on time.
The science, made simple.
Why are there three different lens colors?
Because how much blue light is worth filtering changes with the hour. During the day, a gentle filter is enough to cut eye strain without changing how you see. At dusk and before bed, your body benefits from a progressively deeper filter, closer to warm candlelight.
Which band of light actually matters?
The band running roughly from 415 to 530 nanometers — blue-violet through blue-green — is what most stimulates the retinal cells that set your biological clock, peaking near 480nm. The rest of the visible spectrum has far less impact on your internal clock.
Where do the filtering percentages come from?
From lab reports with spectral transmission curves measured on samples of each of our three lenses. We publish the figures exactly as they come out of those measurements, alongside each tint's light transmission, so you can also see how much visible light gets through.
Does the lens tint change how I see color?
Yes, to different degrees depending on the tint: yellow is barely noticeable, orange adds a perceptible warm cast, and red shifts color perception noticeably — which is why it's recommended indoors only, before bed.
Can I drive in them or use them as sunglasses?
No. Our lenses are designed for indoor use in front of screens and are not certified as sunglasses or for driving. The shift in color perception the tint creates makes them unsuitable behind the wheel, especially the orange and red tints.
Does this replace good sleep habits?
No. Filtering blue light is a complement, not a substitute for habits like cutting screen time before bed, keeping consistent hours and getting natural light during the day.
Important note
Ryva lenses are a general-use optical product with a blue light filter. They are not a medical device: they do not diagnose, treat, cure or prevent any illness or sleep disorder, and they are not a substitute for consulting an eye care professional.
The percentages published on this page come from spectral transmission measurements taken in a laboratory on samples of our lenses, and describe the optical behavior of the filter, not a guaranteed clinical outcome. The information on light, circadian rhythm and hormones is offered for general education and reflects the broad state of research in the field; effects vary from person to person. If you have persistent visual discomfort or sleep problems, consult a health professional.
Our lenses are not certified as sunglasses or for use while driving.