Myopia (Short-sightedness)
Other people have eyes that are too long, so the light focuses in front of the retina (they are short-sighted). This means that they cannot see things clearly if they are far away from them (such as the TV or board at school).
Normally, light is focussed by the cornea and lens to form a sharp image on the retina.
Sometimes the eyeball is too long for the shape of the cornea
… so the light comes to a focus before it reaches the retina.
As a result, objects in the distance are blurred
… although close objects are usually clear.
Short-sightedness can be corrected by glasses or contact lenses.
These lenses correct the vision so that distant objects are clear once again.