Myopia is due to

Options

A. elongation of eye ball
B. irregular change in focal length
C. shortening of eye ball
D. older age

Explanation

**Step-by-Step Solution:**

1. **Understanding Myopia**: Myopia, also known as nearsightedness or short-sightedness, is a common vision condition where distant objects appear blurry while close objects can be seen clearly.

2. **Cause of Myopia**: The primary cause of myopia is the elongation of the eyeball. When the eyeball is too long, light rays coming from distant objects converge at a point in front of the retina instead of directly on it.

3. **Light Convergence**: In a normal eye, light rays from distant objects converge on the retina. However, in myopia, these rays converge before reaching the retina, causing distant objects to appear out of focus.

4. **Corrective Measures**: To correct myopia, concave lenses are used. Concave lenses diverge the light rays before they enter the eye, allowing them to converge at the correct point on the retina.

5. **Conclusion**: Myopia is primarily due to the elongation of the eyeball, which results in the convergence of light rays in front of the retina. This condition can be corrected with the use of concave lenses.