## Core Concept
The question pertains to conditions or locations of lesions within the brain and their effects on vision, specifically asking which one does not affect vision. This involves understanding the neuroanatomy of visual pathways.

## Why the Correct Answer is Right
The correct answer, which is not specified here but implied to be related to a condition or location not affecting vision, likely involves areas or conditions that do not directly interfere with the visual pathway. The visual pathway includes structures from the eyes (retina) to the optic nerves, optic chiasm, optic tracts, lateral geniculate bodies, optic radiations, and finally to the visual cortex (occipital lobe). Lesions affecting any part of this pathway can cause visual disturbances.

## Why Each Wrong Option is Incorrect
- **Option A:** Lesions in certain areas (e.g., optic nerve) can cause loss of vision in one eye, indicating that vision can indeed be affected.
- **Option B:** Similarly, lesions in other areas (e.g., optic chiasm) can cause bitemporal hemianopia, a type of visual field defect.
- **Option C:** Lesions here (e.g., optic tract) can cause homonymous hemianopia, another type of visual field defect.

## Clinical Pearl / High-Yield Fact
A key point to remember is that the visual pathway is complex, and lesions at different levels cause different types of visual field defects. For example, a lesion in the optic nerve causes loss of vision in one eye, while a lesion in the optic chiasm causes bitemporal hemianopia.

## Correct Answer: D.