**Core Concept**
Stereopsis refers to the ability to perceive the depth and distance of objects in the visual field using the slight differences in the images seen by each eye. This is made possible by the binocular disparity between the two eyes, where the brain combines the images from each eye to create a three-dimensional perception.

**Why the Correct Answer is Right**
The correct answer, B. Perception of depth of vision, is the result of the brain's ability to process the binocular disparity between the two eyes. When light enters each eye, it forms an image on the retina, which is then transmitted to the brain. The brain combines these images to create a single perception of depth, allowing us to judge the distance and proximity of objects in our environment. This process is mediated by the lateral occipital complex (LOC) in the brain, which is responsible for depth perception.

**Why Each Wrong Option is Incorrect**
**Option A:** Perception of different colours - This is incorrect because stereopsis is not related to the perception of different colours, but rather to the perception of depth and distance.

**Option C:** Perception of Peripheral visual fields - This is incorrect because stereopsis is specifically related to the perception of depth, not the peripheral visual fields, which are the areas of the visual field outside of the direct line of sight.

**Option D:** Perception of size of an object - This is incorrect because stereopsis is not related to the perception of the size of an object, but rather to the perception of its depth and distance.

**Clinical Pearl / High-Yield Fact**
Stereopsis is an important aspect of binocular vision, and its loss can be indicative of neurological or ophthalmological disorders, such as amblyopia or strabismus. Clinicians should be aware of the importance of stereopsis in assessing visual function and diagnosing related conditions.

**✓ Correct Answer: B. Perception of depth of vision**