## **Core Concept**
Kayser-Fleischer rings are a clinical sign associated with **Wilson's disease**, a genetic disorder characterized by excessive accumulation of copper in the body. These rings are a result of copper deposition in the **Descemet's membrane** of the cornea.

## **Why the Correct Answer is Right**
The correct answer involves the deposition of copper in the peripheral cornea, specifically within the Descemet's membrane. This occurs due to the high concentration of copper in the blood and tissues of patients with Wilson's disease. The Kayser-Fleischer ring is a brownish-yellow discoloration seen at the periphery of the cornea, which is a pathognomonic sign of Wilson's disease.

## **Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because Kayser-Fleischer rings are not related to the lens but are specifically associated with the cornea.
* **Option B:** This option is incorrect as it does not accurately describe the location associated with Kayser-Fleischer rings.
* **Option C:** Although this option might seem plausible because it mentions the cornea, it does not specify the correct structure within the cornea where copper deposition occurs.

## **Clinical Pearl / High-Yield Fact**
A key clinical pearl is that Kayser-Fleischer rings are not only a diagnostic feature of Wilson's disease but are also sometimes seen in other conditions like **primary biliary cirrhosis** and **cryptogenic cirrhosis**. However, their presence is highly suggestive of Wilson's disease, especially in a young patient with neurological symptoms.

## **Correct Answer:** . Cornea (Descemet's membrane).