**Core Concept**
The question pertains to the concept of thermal stress and its effects on the cornea, specifically the development of a corneal condition known as **keratoconus** or **corneal ectasia**. This is a condition characterized by progressive thinning and conical protrusion of the cornea, often associated with mechanical stress and high myopia.

**Why the Correct Answer is Right**
The mechanism behind the development of keratoconus is thought to be related to **mechanical stress** and **thermal stress** on the cornea, leading to **breakdown of the lamellar structure** and subsequent thinning. The cornea is composed of collagen fibrils embedded in a matrix of glycosaminoglycans, which provide its strength and rigidity. High temperatures can disrupt this delicate balance, leading to weakened corneal tissue and increased susceptibility to mechanical stress.

**Why Each Wrong Option is Incorrect**
* **Option A:** Corneal edema is a condition characterized by accumulation of fluid within the corneal stroma, usually due to increased intraocular pressure or endothelial dysfunction, not thermal stress.
* **Option B:** Corneal ulcers are typically caused by infections or trauma, not thermal stress.
* **Option C:** Fuchs endothelial dystrophy is a degenerative disorder of the corneal endothelium, characterized by accumulation of fluid within the corneal stroma, but is not directly related to thermal stress.

**Clinical Pearl / High-Yield Fact**
A useful mnemonic to remember the causes of keratoconus is **"MECHANICS"**: Mechanical stress, Enlarged pupils, Collagen degradation, Heat, Anisometropia, Corneal thinning, Nerve damage, and Increased intraocular pressure.

**Correct Answer: C. Keratoconus**