**Core Concept**
The granular layer of the cornea is a critical component of the corneal stroma, responsible for maintaining corneal transparency and refractive power. An increase in the thickness of this layer can lead to corneal opacity and vision impairment.

**Why the Correct Answer is Right**
The granular layer is composed of tightly packed, homogeneous collagen fibrils, which are crucial for maintaining corneal transparency. An increase in the thickness of this layer is often associated with corneal dystrophies, such as granular corneal dystrophy, which is characterized by the accumulation of abnormal collagen fibrils. This accumulation can lead to a gradual thickening of the granular layer, causing corneal opacity and vision loss.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the granular layer is not associated with the endothelial layer, which is a single layer of cells located at the posterior surface of the cornea.

**Option B:** This option is incorrect because the Bowman's layer is a distinct, acellular layer located between the epithelium and the stroma, and is not directly related to the granular layer.

**Option C:** This option is incorrect because the anterior chamber is the space between the cornea and the iris, and is not related to the thickness of the granular layer.

**Clinical Pearl / High-Yield Fact**
A key clinical correlation to remember is that corneal dystrophies, such as granular corneal dystrophy, often present with a characteristic "granular" appearance on slit-lamp examination, which is due to the accumulation of abnormal collagen fibrils in the granular layer.

**Correct Answer:** B. Bowman's layer.