The retinal images falling on the two retinas are not identical when we see an object with two eyes. Due to a distance of 2 to 2/2 inches between both the eyes, there is a difference between the retina images of the left and right eye. So there is a difference in the visual areas of left and right eye due to the difference in location of their fovea. Left eye has a visual area a little more on the left and the right eye has a visual are a little more on the right. This is called binocular disparity. Inspite of this disparity, when we see with both the eyes, their retinal images merge. We do not have double vision but one stereoscopic vision in three dimensions and perceive depth and distance.