Suspensory ligament is highly tensed when ,

Options

A. Object is very near
B. Object is at infinity
C. Tension of suspensory ligament is independent of the distance of an object
D. Ciliary muscles fully contract

Answer

### Step-by-Step Solution:

1. **Understanding the Role of Suspensory Ligament**: The suspensory ligament, also known as the zonules of Zinn, connects the ciliary body to the lens of the eye. Its primary function is to hold the lens in place and assist in changing the shape of the lens for focusing.

2. **Identifying the Conditions of Tension**: The tension in the suspensory ligament varies depending on the distance of the object being viewed. When focusing on an object, the ciliary muscles either contract or relax, which in turn affects the tension in the suspensory ligament.

3. **Analyzing the Options**:
- **Object is very near**: When an object is close, the ciliary muscles contract, which decreases the tension in the suspensory ligament.
- **Object is at infinity**: When focusing on an object at infinity, the ciliary muscles relax, leading to increased tension in the suspensory ligament.
- **Tension independent of distance**: This statement is incorrect as the tension is directly related to the distance of the object.
- **Ciliary muscles fully contract**: This would decrease the tension in the suspensory ligament, not increase it.

4. **Conclusion**: The suspensory ligament is highly tensed when the object is at infinity because the ciliary muscles are relaxed, allowing the ligament to stretch and hold the lens in a flattened shape for distant vision.

### Final Answer:
The suspensory ligament is highly tensed when the object is at infinity.

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