**Core Concept**
Mummification is the process of preserving a dead body through desiccation, resulting in the formation of a mummified state. The process involves the breakdown of cellular components and the loss of moisture from the body. In the context of the eye, mummification can occur due to the lack of blood supply and the absence of tear production, leading to the desiccation of the cornea.

**Why the Correct Answer is Right**
The cornea is the first part of the eye to undergo mummification due to its high water content and thinness. The cornea lacks a blood supply, which makes it more susceptible to desiccation. As a result, the cornea becomes dry and opaque, leading to a loss of vision. This process can occur rapidly, especially in cases where the eye is exposed to the air or in individuals with pre-existing eye conditions.

**Why Each Wrong Option is Incorrect**
**Option A:** The sclera, the white part of the eye, is the outermost layer and provides structural support to the eye. While the sclera can become dry and brittle, it is not the first part of the eye to undergo mummification.
**Option B:** The iris, the colored part of the eye, is responsible for regulating the amount of light entering the eye. While the iris can become dry and wrinkled, it is not the first part of the eye to undergo mummification.
**Option C:** The retina, the innermost layer of the eye, is responsible for detecting light and sending signals to the brain. While the retina can become damaged, it is not the first part of the eye to undergo mummification.

**Clinical Pearl / High-Yield Fact**
In cases of mummification, the cornea can become so dry and opaque that it requires surgical intervention to restore vision. This highlights the importance of proper eye care and the need for prompt treatment in cases of dry eye or corneal desiccation.

**Correct Answer:** A. The cornea.