Illinois Vision Certification Practice Test

In binocular vision, what must happen for the images to avoid double vision?

1. The images must be fused at the brain level

2. The images must be viewed with one eye closed

3. The images must be adjusted for distance

4. The images must be projected onto the same side of the brain

The correct answer is: The images must be fused at the brain level

For binocular vision to function properly and successfully avoid double vision, it is essential that the images from both eyes are fused at the brain level. This fusion occurs in the visual cortex, where the brain combines the slightly different images received from each eye into a single coherent image. This process allows for depth perception and a unified visual experience. Without this fusion, the brain struggles to integrate the two images, leading to the phenomenon of double vision or diplopia. The other options do not effectively contribute to the prevention of double vision in the same way. Closing one eye may eliminate the visual input from that eye, but it is not a viable solution for maintaining binocular vision. Adjusting for distance primarily influences focus rather than the fusion process required to avoid double images. Lastly, while proper neural processing is crucial, projecting images onto the same side of the brain does not accurately describe how binocular vision is integrated; rather, visual information crosses over and is processed in both hemispheres, which supports the coordination necessary for image fusion.