What are the possible causes of myopia.

Explanation

### Step-by-Step Solution:

1. **Understanding Myopia**: Myopia, commonly known as nearsightedness, is a condition where a person can see nearby objects clearly, but distant objects appear blurry. This occurs because the light rays from distant objects are focused in front of the retina instead of directly on it.

2. **Normal Eye Function**: In a normal eye, parallel rays of light from distant objects converge on the retina, which is the light-sensitive layer at the back of the eye. This allows for a clear image to be formed.

3. **Focus Point in Myopia**: In myopia, the focal point of these parallel rays is located before the retina. This misalignment causes the image to be out of focus, leading to difficulty in seeing distant objects.

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