The Resolution of the Human Eye

In an age of ever-improving technology, the question of the human eye’s resolution is more interesting than ever. Resolution is the ability to see two sources very close together, and is measured in arcminutes, with 60 arcminutes in a degree. The further away two objects are, the smaller the angle separating them—for example, the Hubble Space Telescope has a resolution of 0.0008 arcminutes, which means that if two stars are closer together than that, they appear as a single object. The resolution limit of the human eye varies from person to person, but if you had 20/20 vision your resolution would be 0.6 arcminutes. Our vision isn’t like an image, though; it’s more like a constant video stream, with our eyes moving rapidly and constantly updating the images we see, so the resolution of the human eye is far greater than any camera—it’s the equivalent of 576 megapixels. Potentially, a 576 megapixel image could fool our eyes into thinking it was the real thing, but only if you covered one eye—as soon as both eyes move, you’d be able to detect that the image was flat, not 3D. Intriguing stuff.