Short-sightedness can be treated with laser eye surgery
Myopia occurs when your eyeball is slightly longer or your cornea is more curved than required for clear vision.
This means that when the light rays come together (into focus), they do so slightly in front of rather than on the retina, meaning that the image becomes blurred.
The effect of this is that you cannot see distant objects clearly (for example, the numbers on the front of buses) although your close vision may be very good as your eye is naturally focused at this distance.
Laser eye surgery can correct myopia by changing the shape of the cornea so that its focusing power is matched to the length of the eye.