For the myopic eye, the defect is cured by

Options

A. Convex lens
B. Concave lens
C. Cylindrical lens
D. None of these.

Explanation

### Step-by-Step Solution:

1. **Understanding Myopia**: Myopia, also known as nearsightedness, is a common vision condition where a person can see nearby objects clearly, but distant objects appear blurry. This occurs because the eye is either too long or the cornea has too much curvature, causing light rays to focus in front of the retina instead of directly on it.

2. **Identifying the Problem**: In a myopic eye, the far point (the furthest point at which objects can be seen clearly) is closer than infinity. This means that the eye cannot focus on distant objects properly.

3. **Corrective Measures**: To correct myopia, we need to adjust the way light enters the eye so that it focuses correctly on the retina. This is done using lenses.

4. **Choosing the Right Lens**:
- **Convex Lens**: This type of lens converges light rays and is used for hyperopia (farsightedness), not myopia.
- **Concave Lens**: This type of lens diverges light rays and is used to correct myopia by allowing the light rays to spread out before they enter the eye, effectively moving the focus back onto the retina.
- **Cylindrical Lens**: This type of lens is used for astigmatism, not specifically for myopia.
- **None of These**: This option is incorrect since we do have a corrective lens for myopia.

5. **Conclusion**: The correct lens to cure myopia is a concave lens, as it helps to diverge the light rays, allowing the image to be focused correctly on the retina.

### Final Answer:
The defect of myopia is cured by using a **concave lens**.

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