What phenomenon enables the perception of depth using both eyes?

Stereopsis is the phenomenon that allows individuals to perceive depth through the combined input from both eyes. When we view an object, each eye sees it from a slightly different angle, due to their horizontal separation. The brain processes these two overlapping images to create a single perception of depth. This depth perception is crucial for tasks such as judging distances, which enhances our ability to navigate the three-dimensional world around us.

In this context, while convergence, which refers to the inward movement of the eyes when focusing on a nearby object, and binocular vision, which is the use of both eyes to create a single visual image, contribute to depth perception, they do not solely encapsulate the quality of stereopsis. Unilateral vision refers to vision in one eye, which does not involve depth perception in the same way as the input from both eyes does. Therefore, stereopsis specifically captures the integrated visual processing that leads to our understanding of depth in a way that the other choices do not.