**Core Concept**
Keratoconus is a progressive, non-inflammatory, bilateral eye disease characterized by thinning and conical protrusion of the cornea, leading to vision impairment. This condition is often associated with ectasia of the cornea, which affects its refractive power and optical clarity.

**Why the Correct Answer is Right**
The correct answer is related to the pathophysiology of keratoconus. Keratoconus is caused by a combination of genetic and environmental factors, leading to a weakening of the corneal tissue. This weakening results in the cornea bulging outward, causing a conical shape and vision problems. The condition is often associated with an increased sensitivity to ultraviolet (UV) light, which may trigger the onset of keratoconus in susceptible individuals.

**Why Each Wrong Option is Incorrect**
**Option A:** Keratoconus is not typically associated with an allergic response, as it is a non-inflammatory condition.
**Option B:** While keratoconus can be exacerbated by eye rubbing, it is not a primary cause of the condition.
**Option C:** The correct answer is not provided, but we will address it below.

**Clinical Pearl / High-Yield Fact**
Keratoconus often presents with irregular astigmatism and myopia, which can be exacerbated by eye rubbing or other factors. It is essential to recognize the signs and symptoms of keratoconus to provide timely treatment and prevent further vision loss.

**Correct Answer:**
(Insert correct option letter here, e.g., A, B, C, D)