What are the possible causes of hypermetropia ?

Explanation

### Step-by-Step Solution

1. **Understanding Hypermetropia**: Hypermetropia, also known as farsightedness, is a vision condition where distant objects can be seen clearly, but close ones do not come into proper focus. This occurs when the image of nearby objects is focused behind the retina.

2. **Normal Vision**: In a normal eye, the lens focuses light rays from nearby objects directly onto the retina, allowing for clear vision. The distance between the lens and the retina is optimal for focusing images.

3. **Cause 1 - Eye Structure**: One of the primary causes of hypermetropia is the anatomical structure of the eye. If the eyeball is shorter than normal or if there is a reduction in the distance between the lens and the retina, the light rays from nearby objects converge behind the retina instead of on it. This can happen due to a contraction of the eyeball.

...