Which skill is impaired when binocular vision is lost?

When binocular vision is lost, depth judgment is significantly impaired. Binocular vision refers to the ability of both eyes to work together to create a single image, which is crucial for accurately perceiving depth and distance. The brain processes visual information from both eyes to gauge how far away objects are from the observer, a process known as stereopsis. This ability to perceive depth is essential for activities such as driving, catching a ball, or navigating through space.

In contrast, color discrimination, night vision, and visual acuity are primarily influenced by other factors such as the functionality of the individual eyes, the retina, and the rods and cones in the visual pathways. While loss of binocular vision can affect the overall visual experience, depth judgment specifically relies on the coordinated input from both eyes. Therefore, the correct answer is depth judgment, which is directly affected when binocular vision is impaired.