Magic Eye

A Magic Eye is a type of stereogram, specifically an autostereogram, that presents a two-dimensional image which, when viewed correctly, creates the illusion of a three-dimensional (3D) scene. The viewer must overcome the normal automatic coordination between accommodation (focus) and vergence (eye convergence) to perceive the hidden 3D image.

These stereograms typically appear as a repeating pattern of seemingly random dots or shapes. The 3D effect is achieved through subtle variations in the horizontal spacing of these repeating elements. These variations represent depth information, allowing the brain to interpret the flat image as having depth when the eyes are properly focused and aligned.

To view a Magic Eye image, most people must relax their eyes and either cross their eyes slightly (wall-eyed viewing) or focus as if looking through the image to a point far behind it (parallel viewing). The specific technique that works best can vary from person to person. Success in viewing the 3D image relies on the brain's ability to fuse the slightly different images received by each eye.

The popularity of Magic Eye images peaked in the 1990s with the publication of numerous books featuring these stereograms. The term "Magic Eye" is often used generically to refer to autostereograms, although technically it is a trademarked name.