The middle vascular coat that darkens the eye chamber and prevents refraction by absorbing the light rays is

Options

A. choroid
B. sclera
C. retina
D. cornea

Answer

To solve the question regarding the middle vascular coat of the eye that darkens the eye chamber and prevents refraction by absorbing light rays, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Structure of the Eye**:
- The human eye consists of several parts, including the cornea, lens, retina, and various layers that surround these structures.

2. **Identifying the Middle Vascular Coat**:
- The question specifies a "middle vascular coat." In the context of the eye, this refers to the layer that contains blood vessels and is responsible for providing nourishment and absorbing excess light.

3. **Function of the Middle Vascular Coat**:
- The middle vascular coat's primary function is to darken the eye chamber and prevent excessive light from causing refraction. This is crucial for maintaining clear vision and protecting the inner structures of the eye.

4. **Naming the Correct Structure**:
- The specific layer that fulfills these functions is known as the "choroid." The choroid is located between the retina and the sclera (the outer layer of the eye) and is rich in blood vessels.

5. **Conclusion**:
- Therefore, the answer to the question is that the middle vascular coat that darkens the eye chamber and prevents refraction by absorbing light rays is the **Choroid**.