Question

But if the two eyes receive totally different images, the brain can't combine the two images and a condition called _________ occurs, in which the observer perceives either the left-eye image or the right-eye image, but not both at the same time.

Answer 1

Binocular rivalry is a condition that occurs when the brain cannot fuse significantly different images from each eye into a single perception, leading to an alternation between the two images rather than simultaneous perception.

Step-by-step explanation:

When both of our eyes look at an object, they receive slightly different images due to their separate positions on the face. Normally, the brain fuses these two images to create a single, three-dimensional perception of the world, which includes the illusion of depth. This process is crucial for visual clarity and depth perception. The brain's ability to fuse two images into one is influenced by many factors including alignment of the eyes, the similarity of the images, and neurological efficiency.

However, if the images are too different, as might occur with an irregularity such as astigmatism or due to an issue with the visual pathways, such as an impact on the optic chiasm from a growth in the pituitary gland, the brain may struggle to combine them effectively. As a result, rather than blending the two images, the brain might alternate between them, giving rise to the phenomenon known as binocular rivalry. People with this condition may not necessarily lose peripheral vision as in bilateral hemianopia, but they will experience difficulty with binocular vision, affecting their perception of depth.