EnChroma glasses use specially designed filters that selectively block narrow bands of light to increase the contrast between colors that look similar to people with red-green color vision deficiency. They don’t cure color blindness or create new color perception from scratch. Instead, they work by cleaning up the signal that your existing color-sensing cells send to your brain, making it easier to tell reds, greens, and browns apart.
The Overlap Problem in Color Vision
Normal color vision relies on three types of light-sensitive cells in the retina called cones. One type responds most to short wavelengths (blue light), one to medium wavelengths (green light), and one to long wavelengths (red light). Your brain compares the signals from all three types to determine what color you’re seeing.
In the most common forms of color blindness, the medium and long wavelength cones respond to ranges of light that overlap more than they should. Instead of sending the brain two clearly different signals for red and green, these cones send signals that are too similar. The brain can’t reliably distinguish between them, so reds, greens, oranges, and certain browns blend together or look nearly identical. This is called anomalous trichromacy, and it affects roughly 1 in 12 men and 1 in 200 women.
How Notch Filters Separate Colors
EnChroma lenses contain what optical engineers call “notch filters.” Rather than tinting all light evenly like ordinary sunglasses, these filters cut out precise, narrow slices of the light spectrum, specifically the wavelengths where the medium and long cone responses overlap the most. By removing that overlapping light, the filter increases the contrast between the signals the two cone types send to the brain.
Think of it like two radio stations broadcasting on frequencies that are too close together. You hear static and garbled audio because the signals bleed into each other. A notch filter is like removing the interfering frequency band so each station comes through more clearly. The glasses don’t add any new information. They subtract the noise so the signals your cones already produce become more distinct from one another.
This filtering also shifts the overall color balance of what you see, boosting the apparent contrast between short wavelengths (blues) and the middle-to-long wavelength range (greens, reds, oranges). That’s why many users report that colors look more vivid and saturated when they first put the glasses on.
Why They Only Work for Some People
EnChroma glasses require that all three cone types are present and functional in your retina. They’re designed for anomalous trichromats, people whose cones exist but have shifted sensitivity ranges. For these individuals, the filters can meaningfully improve the separation between cone signals.
The glasses are far less effective for dichromats, people who are completely missing one type of cone. If you only have two cone types, there’s no overlapping signal to clean up. Removing a slice of the spectrum doesn’t help because the missing cone’s signal was never there to begin with. This is an important distinction, because roughly 25% of people with red-green color deficiency are dichromats rather than anomalous trichromats.
Even among anomalous trichromats, results vary significantly depending on severity. A 2018 study published in Optics Express found that EnChroma glasses only improved clinical test scores in two out of their test subjects, moving them from “severe” to “moderate” classifications. On a more detailed color arrangement test, the glasses did not significantly improve error scores for the group overall. The researchers concluded that while the glasses change perceived color, they don’t allow people with color vision deficiency to achieve normal color vision. In some cases, the filters helped with recognizing certain colors while making others harder to identify.
The Brain’s Adjustment Period
Many users don’t experience the full effect immediately. EnChroma recommends wearing the glasses for extended periods to give the brain time to recalibrate. This isn’t marketing fluff. There’s genuine neuroscience behind it.
Your visual system constantly adjusts how it interprets incoming signals, a process called chromatic adaptation. When the glasses suddenly deliver a different balance of color information, the brain needs time to learn how to use that new input. Research published in Optics Express found something particularly interesting: anomalous trichromats who wore EnChroma glasses over an extended period showed improved color discrimination even after removing the glasses. Their brains had adapted to weight the signals from their cones differently, demonstrating real neural plasticity in the chromatic response. In controlled lab settings, researchers typically allowed at least 30 minutes of adaptation before testing, but the longer-term perceptual changes suggest that days or weeks of regular use may produce more noticeable results.
Indoor vs. Outdoor Lens Options
EnChroma offers different lens categories depending on lighting conditions. Their naming system follows standard optical industry classifications. Cx1 lenses are designed for indoor and low-light environments, transmitting 44 to 80 percent of incoming light. Cx3 lenses function like sunglasses, transmitting only 9 to 18 percent of light, and are built for bright outdoor conditions.
This matters because the notch filtering effect depends on having enough light hitting the lenses. In dim environments, an outdoor lens would make everything too dark to see well, reducing any color enhancement benefit. The indoor lenses let more total light through while still applying the selective filtering. Outdoor lenses can afford to block more light overall because there’s plenty available, and the stronger filtering can sometimes produce a more dramatic color separation effect in bright, natural daylight.
What the Glasses Actually Change Day to Day
In practical terms, most users with moderate anomalous trichromacy report that the glasses make certain everyday distinctions easier: telling ripe from unripe fruit, reading color-coded charts, noticing the difference between green and brown leaves, or distinguishing indicator lights. Colors often appear more saturated and vivid, which accounts for the strong emotional reactions common in online videos.
What the glasses don’t do is equally important to understand. They don’t let you “see new colors” in the way a person with normal vision sees them. They shift and enhance the color information your eyes already collect. The experience is closer to turning up the contrast on a slightly washed-out photo than to suddenly switching from black-and-white to color. And because they work by removing certain wavelengths, they can occasionally make some color pairs harder to distinguish while making others easier. The trade-off depends on your specific cone sensitivity profile, which is why individual experiences vary so widely.
For someone with mild to moderate red-green deficiency and all three cone types intact, the glasses offer a genuine perceptual enhancement. For someone with severe deficiency or a missing cone type entirely, the effect ranges from minimal to nonexistent. There’s no way to predict your exact response without trying them, which is why EnChroma offers a return window on most purchases.