binocular disparity

Binocular disparity is a key element of binocular vision, which is the ability to perceive depth using two eyes. While one eye can perceive depth through monocular cues, binocular vision adds two more factors: convergence of the eyes and the difference between the images seen by each eye.1

This difference in images, known as binocular disparity, is crucial for stereoscopic vision. When you look at an object, each eye captures a slightly different image due to their separate positions. The brain fuses these two images, and the degree of disparity helps determine the object's distance and three-dimensional form. If the disparity is too large, the brain may see double images or suppress one, but within a certain range (Panum's fusional area), it allows for the perception of depth. Specialized nerve cells in the brain are responsible for detecting these disparities and contributing to our sense of three-dimensionality.12