Most of us move through the world pretty sure that the colors and hues we’re seeing around us are shared with everyone else—that if I call a stoplight red, everyone around me will agree that it’s red.

That’s not everyone’s experience, however. According to the National Eye Institute, as many as 8 percent of men and 0.5 percent of women with Northern European ancestry have deuteranopia,—the most common form—in which people have trouble distinguishing red and green hues. .

When it comes to navigating the online world, web designers can make it easier for color-vision impaired people to get around the internet.Shows You the Internet as If You Were Colorblind

Web developer Andrew VanNess created Colorblindly, a Chrome extension that changes your browser’s display colors to reflect how people with different types of colorblindness see the world. This can help designers assess the accessibility of their sites, for everyone.

The extension “places a CSS filter over the webpage that modifies color ratios in line with actual types of colorblindness,” VanNess wrote on the app’s Github entry.

Browsing the web through the view of someone with various types of colorblindness is eye-opening. Switching to achromatomaly, where only some blue hues are visible, saps most of the saturation out of images; achromatopsia, or total color blindness, sucks the color out completely. Protanopia (red color blindness) and deuteranopia are the trippiest—most colors appear to be reversed.