**Core Concept**
The refractive index of a medium is a measure of how much it bends light as it passes through it. In the context of the eye, the refractive indices of different components determine the overall optical power of the eye. The vitreous humor is the clear gel-like substance that fills the space between the lens and the retina.

**Why the Correct Answer is Right**
The vitreous humor has a refractive index of approximately 1.33, which is higher than that of the aqueous humor (1.33) and the cornea (1.376). This higher refractive index helps to maintain the eye's overall refractive power and contributes to the sharpness of vision. The vitreous humor's refractive index is also similar to that of the lens, allowing for smooth transition of light as it passes through the eye.

**Why Each Wrong Option is Incorrect**
**Option A:** 1.00 - This value is too low and corresponds to the refractive index of air, which is not relevant to the vitreous humor.
**Option B:** 1.50 - This value is too high and does not accurately represent the refractive index of the vitreous humor.
**Option C:** 1.90 - This value is also too high and does not match the known refractive index of the vitreous humor.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that the refractive indices of different eye components vary, and understanding these values can help in diagnosing and managing various eye conditions, such as refractive errors and cataracts.

**Correct Answer: C. 1.33**