Myopia (or near-sightedness) is a condition in which people are able to see close objects clearly but struggle to identify objects further away. It is the most common type of refractive error and is thought to affect one in three people in the UK. The condition generally starts in puberty and becomes gradually worse until the eye is fully grown. People with myopia generally have difficulty clearly seeing a television screen or reading road signs.
For the eye to produce a perfectly clear image the cornea must be evenly curved and the eye needs to be the correct length. Myopia occurs if the eyeball is too long or the cornea is too curved. This causes the light entering the eye to not focus correctly resulting in a blurry image being sent to the brain.