Which of the following is an effect of a large lesion near the optic chiasm?

A large lesion near the optic chiasm is particularly impactful due to the organization of visual pathways in the brain. The optic chiasm is the point where the optic nerves from each eye meet and partially cross over. Lesions in this area can disrupt the transmission of visual signals from both eyes to the brain.

When such a lesion occurs, it can lead to complete visual loss depending on the extent and location of the damage, as it may affect both the nasal retina fibers from both eyes that carry crucial visual information from the peripheral visual field. This can result in a significant loss of vision, especially if the lesion is extensive enough to impact both pathways.

In contrast, double vision typically arises from problems with the muscles that control eye movement or issues with the cranial nerves, which is not directly related to optic chiasm lesions. Tunnel vision would indicate a loss of peripheral vision, often caused by other conditions rather than an optic chiasm lesion. Color vision deficiency is usually linked to issues within the photoreceptors in the retina or the visual processing areas of the brain, rather than lesions affecting the optic chiasm specifically. Thus, the effect of a large lesion near the optic chiasm leading to complete visual loss is a direct outcome