**Core Concept**
The critical angle is the angle of incidence above which total internal reflection occurs, and it is crucial for understanding the optics of the eye, particularly at the cornea-air interface. This concept is based on **Snell's law** and **refraction** principles. The cornea is the primary refractive surface of the eye.

**Why the Correct Answer is Right**
The critical angle at the cornea-air interface is approximately 46 degrees, which is the angle beyond which light is completely reflected back into the cornea. This occurs because the **refractive index** of cornea is about 1.376 and that of air is approximately 1.000.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not accurately represent the critical angle at the cornea-air interface.
**Option B:** Similarly, this option is not the correct value for the critical angle.
**Option C:** This option is also incorrect as it does not match the known critical angle.

**Why Each Wrong Option is Incorrect (Continued)**
**Option D:** This option is incorrect because the actual critical angle is less than this value.

**Clinical Pearl / High-Yield Fact**
Remembering the critical angle is crucial for understanding **ophthalmological** conditions and the optics of the eye. The critical angle helps in designing **intraocular lenses** and other **ophthalmic devices**.

**Correct Answer:** Correct Answer: C. 46 degrees.