## **Core Concept**
The refractive index of a medium is a measure of how much it bends light that enters it. In the context of the eye, different parts have different refractive indices, which contribute to the eye's overall ability to focus light on the retina. The cornea, being the outermost layer of the eye, plays a significant role in this process.

## **Why the Correct Answer is Right**
The cornea has a refractive index of approximately 1.376. This value is crucial for understanding how light is initially bent as it enters the eye. The cornea contributes significantly to the eye's total optical power, primarily because of the significant difference in refractive index between air (approximately 1.00) and the cornea. This large change in refractive index as light moves from air into the cornea causes a substantial amount of bending of light.

## **Why Each Wrong Option is Incorrect**
- **Option A:** 1.3 - This value is lower than the actual refractive index of the cornea. While close, it does not accurately represent the cornea's refractive index.
- **Option B:** 1.4 - This value is higher than the actual refractive index of the cornea. It overestimates the bending effect of the cornea on light.
- **Option D:** 1.5 - This value is significantly higher than the actual refractive index of the cornea and does not accurately represent any part of the eye's refractive system.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that the cornea contributes about 2/3 of the eye's total refractive power, with the lens contributing the remaining 1/3. This is because the cornea is the first surface that light encounters and the change in medium from air to cornea results in significant bending of light.

## **Correct Answer:** C. 1.376.