When we look at our environment, we immediately detect and recognize they objects, buildings, and people surrounding us. Our perception of fine detail, lines, edges, color, movement, and depth are all important for building up representations of these objects, scenes, and people. This processing occurs rapidly and is achieved effortlessly by the visual system as we take in the world with both eyes. Imagine what it might be like to not have vision through two eyes – to be completely blind. We would have to use our remaining intact sensory systems to their fullest capacity in order to interact with the world. Our senses of touch, taste, smell, and hearing would become significantly more important to allow us to connect with and understand our world.
Now instead, consider what it might be like to lose vision in only one eye. With one completely nonfunctional eye and one intact eye, our visual system would still receive light input through the intact remaining eye. So, one might ask, how could having only one eye affect our ability to see? From a systems point of view, the physical light input to our visual system would be reduced by half compared to the intact binocular visual system.