## **Core Concept**
Keratoconus is a progressive eye disease characterized by thinning and conical deformation of the cornea, leading to visual impairment. It involves changes in corneal curvature and structure.

## **Why the Correct Answer is Right**
The correct answer involves understanding the pathophysiology of keratoconus. In keratoconus, there is an increase in the curvature of the cornea (**a) ↑ curvature of cornea**), which leads to **astigmatism (b) Astigmatism)** due to the irregular shape of the cornea. A **Kernig's sign or Fleischer's ring (c) K.F. ring seen)**, often referred to in the context of keratoconus, is not typically described as a "ring" but is associated with the thinning and conical protrusion.

## **Why Each Wrong Option is Incorrect**
- **Option D: Thick cornea** - Keratoconus is associated with thinning of the cornea, not thickening.
- **Option E: Soft contact lens used** - While contact lenses are used in the management of keratoconus, rigid gas permeable (RGP) lenses or hybrid lenses are more commonly used to correct the irregular astigmatism and provide a more uniform surface for vision correction, rather than soft contact lenses.

## **Clinical Pearl / High-Yield Fact**
A key clinical feature of keratoconus is the presence of **myopia and astigmatism** due to the increased curvature of the cornea. Early detection and proper management can help prevent significant visual impairment.

## **Correct Answer:** .