This is one of those things from the internet that went viral in a matter of hours. It had all the users in a craze, struggling to understand how it works. Basically, what happens is that if you fix your eyes on the image at any point without blinking and without moving, its content disappears. The effect only takes about fifteen or twenty seconds to manifest, but the origin of the illusion goes back to more than 200 years into the past.
It all started thanks to a post on Reddit by the user NightBreeze13. A simple image with several colors, white background and diffuse edges. If you look at the image for twenty seconds (in some cases it may take up to a minute), all the colors disappear. Sometimes, one of those colors “resists” and stays for a longer time, but the illusion works very well as long as there is no flicker or movement. First of all, the answer is no: you are not a freak, and there is no problem with yout eyes. And secondly… this is what is going on with this image?
The magic of an internet search confirms that the image has been in circulation since at least 2011, and that the illusion is a product of the Troxler effect, originally identified by the Swiss doctor Ignaz Paul Vital Troxler in the year 1804. In a relaxed state, our vision adapts to all external stimuli, and when those stimuli do not change, they become ignored, if you will. Any basic movement in the environment (and that of our own eyes) is enough to break the effect, but by standing still staring at the image, the colors vanish. Another example of a neuronal adaptation that does not involve our eyes is to put on a pair of socks. At first we can feel its texture and temperature difference, but as the hours go by, those sensations disappear, as do the colors in this image.
Another interesting aspect of the Troxler effect is that the image does not need to be entirely static. The second image is an animated GIF with a black plus sign in the center of a circle formed by lilac dots. If we focus our gaze on the black plus, the dot that appears and “disappears” will turn green, and after a few seconds, it will begin to devour the purple points as if it was a Pac-man, leaving only the gray background.
Sauce: The Verge
