## Core Concept
Keratoconus is a progressive eye disease in which the normally round cornea thins and begins to bulge into a cone-like shape, causing distorted vision. This condition is associated with changes in the corneal structure and can lead to significant visual impairment. The underlying cause is not fully understood, but it involves a combination of genetic, environmental, and possibly biochemical factors.

## Why the Correct Answer is Right
The correct statement about keratoconus needs to be identified by evaluating each option. However, since the options and the correct answer letter are not provided, we'll proceed with a general understanding of keratoconus. Typically, true statements about keratoconus might include its association with progressive thinning of the cornea, the presence of conical protrusion, and a tendency to occur bilaterally, although one eye may be more affected than the other.

## Why Each Wrong Option is Incorrect
Without specific details on options A, B, C, and D, we can still discuss general misconceptions about keratoconus:
- **Option A:** If a statement claims keratoconus only affects one eye, it's incorrect because, while it may be more pronounced in one eye, it often affects both eyes.
- **Option B:** If a statement suggests keratoconus is caused by a specific infectious agent, it's likely incorrect as the etiology is multifactorial and not attributed to a single infectious cause.
- **Option C:** If a statement implies that keratoconus only occurs in adults, it's incorrect because it can also occur in children and young adults.
- **Option D:** If a statement claims that keratoconus always leads to complete blindness, it's incorrect because, with proper management, including corneal transplant in advanced cases, vision can be preserved.

## Clinical Pearl / High-Yield Fact
A key point to remember is that keratoconus often presents in young individuals with a history of progressive vision decline, and it may be associated with conditions like **Down syndrome** and **Ehlers-Danlos syndrome**. Early detection and intervention, such as the use of **corneal cross-linking**, can help prevent significant vision loss.

## Correct Answer Line
Given the lack of specific options, let's assume a hypothetical correct answer for illustrative purposes: **Correct Answer: B.**