Depth perception is the ability to see the world in 3 dimensions and by doing so to be able to estimate the distance between objects. Retinal disparity<span> is defined as the way that your left eye and your right eye view slightly different images. </span> Convergence refers to the eyes' disposition to rotate inward toward each other in a coordinated manner in order to focus effectively on nearby objects. <span>
</span>Disparity and convergence are the two important things that help us to judge distance. W<span>hen looking at a close-up object, your eyes angle inwards towards each other (you become slightly cross-eyed). The extra effort used by the muscles on the outside of each eye gives a clue to the brain about how far away the object is. This is convergence.</span>
